Thursday
May 23, 2013

# Homework Help: Science: Physics

Physics
An electric motor develops 70 kw of power as it lifts a loaded elevator 28.5 m in 42 seconds. How much force does the motor exert?
Wednesday, February 13, 2013 at 3:23pm

physics
Ricardo and Jane are standing under a tree in the middle of a pasture. An argument ensues, and they walk away in different directions. Ricardo walks 24.0 in a direction 60.0 west of north. Jane walks 10.0 in a direction 30.0 south of west. They then stop and turn to face each ...
Wednesday, February 13, 2013 at 3:19pm

physics
Vector = -1.00 + -2.00 and vector = 3.00 + 4.00 . What are the magnitude and direction of vector = 3.00 + 2.00?
Wednesday, February 13, 2013 at 3:17pm

physics
A ship leaves the island of Guam and sails a distance 280 at an angle 39.0 north of west. 1.In which direction must it now head so that its resultant displacement will be 125 directly east of Guam? (Express your answer as an angle measured south of east) 2.How far must it sail...
Wednesday, February 13, 2013 at 3:15pm

physics
An apple falls from an apple tree growing on a 20° slope. The apple hits the ground with an impact velocity of 5.7 m/s straight downward. What is the component of the apple's impact velocity parallel to the surface of the slope?
Wednesday, February 13, 2013 at 3:12pm

Physics
A 8.38g bullet is fired into a 4.60kg block suspended as in the figure. The bullet stops in the block, which rises 15.0cm above its initial position. Find initial speed of the bullet.
Wednesday, February 13, 2013 at 2:38pm

Physics
A person stands 2.0 m away from the reflecting surface of a plane mirror. What are the image characteristics?
Wednesday, February 13, 2013 at 2:36pm

Physics
A small dog sits 1.5 m in front of a plane mirror. Where is the dog's image in relation to the mirror?
Wednesday, February 13, 2013 at 2:35pm

Physics
A woman 2.00 m tall stands 3.5 m in front of a plane mirror. (a) What is the minimum height the mirror must be to allow the woman to view her complete image from head to foot? Assume that her eyes are 10 cm below the top of her head.(b) What would be the required minimum ...
Wednesday, February 13, 2013 at 2:35pm

Physics
A woman fixing her hair holds a plane mirror 30 cm away from the front of her face so as to look into a plane mirror on the bathroom wall behind her. She is 90 cm from the wall mirror. Approximately how far does the image of the back of her head appear in front of her?
Wednesday, February 13, 2013 at 2:34pm

physics
A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from the impact: one travels in the air and the other in the concrete, and they are 2.7s apart. speed of sound in air is 343 m/s and concrete is 3000 m/s
Wednesday, February 13, 2013 at 2:31pm

Physics
A string requires a 191.0 N force in order to break. A 1.75 kg mass is tied to this string and whirled in a vertical circle with a radius of 1.92 m. The maximum speed that this mass can be whirled without breaking the string is Again I just need the formula!
Wednesday, February 13, 2013 at 1:44pm

Physics
A 2.5 kg object is whirled in a vertical circle whose radius is 0.89 m. If the time of one revolution is 0.94 s, the magnitude of the tension in the string (assuming uniform speed) when it is at the top is I just need the formula and it doesn't even have to be manipulated.
Wednesday, February 13, 2013 at 1:44pm

Physics
A block of mass 17.9 kg supported by a vertical massless cable is initially at rest. The block is then pulled upward with a constant acceleration of 2.01 m/s2. What is the tension in the cable? What is the magnitude of the net force acting on the mass? What is the speed of the...
Wednesday, February 13, 2013 at 12:42pm

Physics (vectors)
Please help me with this question about vectors. Thanks. If you are given a graph with a vector starting at the point (1,-1)and the arrow goes to the point (0,-4). What is the vector in rectangular coordinate? I answered (0,-3), but the coordinate for x is wrong and I can'...
Wednesday, February 13, 2013 at 12:41pm

Physics
A ball is thrown upwards at 15m/s from a window 20 metres above the ground. Find: a)How long the ball the takes to reach the level of the window b)How much longer it takes to reach the ground? c)What speed it takes to reach the ground?
Wednesday, February 13, 2013 at 12:19pm

physics!
The waterfall "Angel Falls" in Venezuela is the world's tallest at h=979 m. Assume that the water's velocity on the top of the falls and on the bottom of the falls (after it hits the ground and begins to flow away) is equal, and that no total energy is lost ...
Wednesday, February 13, 2013 at 12:08pm

physics!!!!!!!!!!!!!!!!!
A few years ago, a movie came out about a soldier, John Carter, who was transported to Mars and could perform amazing feats of strength and jumping due to the lower Martian gravity. The surface gravity of Mars is 0.38 times that of earth. If John could lift 100 kg on earth (...
Wednesday, February 13, 2013 at 12:06pm

Physics
A popular amusement park ride looks like a huge cylinder of radius 3 m, where people stand up along the vertical walls on top of a floor which can drop away. The cylinder begins to rotate faster and faster, and when it reaches its highest speed the floor drops away. Clearly ...
Wednesday, February 13, 2013 at 11:55am

physics!!!!!!!!!!
If you ever watch track and field at the Olympics, you'll notice that the starting points of the runners are not even if the race is run on a curve and the runners have to run in lanes. This is to offset the fact that the distances along each lane are unequal on a curve. ...
Wednesday, February 13, 2013 at 11:52am

Physics (vectors)
Could you please help me with this exercise? Thanks. Adding and substracting vectors Solve for the unknown variables: (a) (a, b) + (3, 0) = (6, 7) (b) (11, c) + (d, 5) = (-12, −3) (c) (5, 5) + (e, 4) = (2, f) (d) (-1, −3) − (5, g) = (h, 2)
Wednesday, February 13, 2013 at 11:52am

Physics (vectors)
Could you please help me with this exercise? Thanks. Adding and substracting vectors Solve for the unknown variables: (a) (a, b) + (3, 0) = (6, 7) (b) (11, c) + (d, 5) = (-12, −3) (c) (5, 5) + (e, 4) = (2, f) (d) (-1, −3) − (5, g) = (h, 2)
Wednesday, February 13, 2013 at 11:18am

physics
In a specific region of interstellar space the atomic composition of gaseous matter is 89.1% atomic hydrogen and 10.9% helium, the temperature is 27K and the pressure is 2.58x10^-15Pa. What is the density of matter in this region? What is the particle density?
Wednesday, February 13, 2013 at 8:27am

physics
A student wishes to measure the resistivity of glass. A teacher suggests that its resistivity is of the order of 10^6 Ω m which is very large. Resistivity ρ is defined by the equation: ρ = RA / l where R is resistance, A is cross-sectional area and l is the ...
Wednesday, February 13, 2013 at 4:57am

Physics (Acceleration)
Determine the final velocity of a proton that has an initial velocity of 2.35 x 10^5 m/s, and then is accelerated uniformly in an electric field at the rate of -1.10 x x 10^12 m/s squared for 1.50 x 10^-7 s.
Wednesday, February 13, 2013 at 4:08am

Physics
A 2.5 kg object is whirled in a vertical circle whose radius is 0.89 m. If the time of one revolution is 0.94 s, the magnitude of the tension in the string (assuming uniform speed) when it is at the top is
Tuesday, February 12, 2013 at 11:09pm

Physics
A student has a weight of 650 N. While riding on a roller-coaster this same student has an apparent weight of 1.97 x 103 N at the bottom of a loop that has a radius of 17.0 m. The speed of the roller-coaster is I just need the forumla, doesn't even have to be manipulated.
Tuesday, February 12, 2013 at 11:08pm

Physics
A string requires a 191.0 N force in order to break. A 1.75 kg mass is tied to this string and whirled in a vertical circle with a radius of 1.92 m. The maximum speed that this mass can be whirled without breaking the string is
Tuesday, February 12, 2013 at 11:05pm

Physics
A quantity of monatomic ideal gas expands adiabatically from a volume of 2.0 liters to 6.0 liters. If the initial pressure is P0, what is the final pressure?
Tuesday, February 12, 2013 at 10:55pm

physics
A mass m = 88.0 kg slides on a frictionless track that has a drop, followed by a loop-the-loop with radius R = 15.8 m and finally a flat straight section at the same height as the center of the loop (15.8 m off the ground). Since the mass would not make it around the loop if ...
Tuesday, February 12, 2013 at 9:37pm

physics
A pumpkin with a mass of 3.0 kg is launched from a catapult at an initial height of 3.5 m off the ground, with an initial speed of 16.2 m/s. What height is the pumpkin at when the speed is half its initial speed?
Tuesday, February 12, 2013 at 8:23pm

physics
The four tires of an automobile are inﬂated to a gauge pressure of 1.7 × 10 5 Pa. Each tire has an area of 0.023 m2 in contact with the ground. Find the weight of the automobile. Answer in units of N
Tuesday, February 12, 2013 at 7:46pm

physics
a 5-kilowatt source powers a motor that is lifting a 30 kg mass straight up. how far will the mass move in 6 seconds
Tuesday, February 12, 2013 at 7:45pm

Physics
Proper design of automobile braking systems must account for heat buildup under heaving braking. Calculate the thermal energy dissipated from brakes in a 1360-kg car that descends a 13.5° hill. The car begins braking when its speed is 88 km/h and slows down to a speed of ...
Tuesday, February 12, 2013 at 6:45pm

Physics
The orbit of a Moon about its planet is approximately circular, with a mean radius of 2.24 × 10 8 m. It takes 35.5 days for the Moon to complete one revolution about the planet. Find the mean orbital speed of the Moon. Answer in units of m/s Find the Moon’s ...
Tuesday, February 12, 2013 at 6:45pm

Physics
The period of the earth around the sun is 1 year and its distance is 150 million km from the sun. An asteroid in a circular orbit around the sun is at a distance 475 million km from the sun. What is the period of the asteroid’s orbit? Answer in units of year
Tuesday, February 12, 2013 at 6:43pm

Physics
An athlete whirls a 7.17 kg hammer tied to the end of a 1.5 m chain in a horizontal circle. The hammer moves at the rate of 1.76 rev/s. What is the centripetal acceleration of the hammer? Assume his arm length is included in the length given for the chain. Answer in units of m...
Tuesday, February 12, 2013 at 6:42pm

Physics
A coordinate system (in meters) is constructed on the surface of a pool table, and three objects are placed on the coordinate system as follows: a 0.8 kg object at the origin, a 2.8 kg object at (0 m,1.7 m), and a 4.4 kg object at (3.8 m,0 m). Find the resultant gravitational ...
Tuesday, February 12, 2013 at 6:41pm

physics
If something has a longer MHz, does it have a longer wavelength
Tuesday, February 12, 2013 at 5:51pm

Physics
A man carries a 10 kg sack of groceries in his arms with a force of 50 N as he walks forward a distance of 10 m. How much work has he done?
Tuesday, February 12, 2013 at 5:34pm

University Physics
Consider this traffic problem that is played out in many communities everyday! A car is cruising down the highway of life @ 25m/s in a 3-m long compact car when he comes upon an intersection with a stop sign. At the instant that he is 45 m away from the entrance to the ...
Tuesday, February 12, 2013 at 5:25pm

physics
please help:- Two capactiors of 14microfarror and 6 microfarror are connected in parallel with a series 10microfarror capacitor across a 100v dc supply a)total capactiance b)charge on each capacitor c)voltage across each capacitor d) energy stored in each capacitor
Tuesday, February 12, 2013 at 5:04pm

physics
list and explain in full details 5 locking devices
Tuesday, February 12, 2013 at 4:59pm

physics
if a proton and an electron are released when they 2.0 x 10^-10 m apart, find the initial acceleration of each of them
Tuesday, February 12, 2013 at 4:45pm

physics
A spacecraft is on a journey to the moon. At what point, as measured from the center of the earth, does the gravitational force exerted on the spacecraft by the earth balance that exerted by the moon? This point lies on a line between the centers of the earth and the moon. The...
Tuesday, February 12, 2013 at 4:27pm

Physics
A spacecraft of mass 2000kg, moves at a constant speed of 7800m.s- in space. the main engine switched on for 10s during which time the exhaust gases travels at 10 000m.s-. As a result of this, the craft travels at 8000m.s- after 10s. Calculate the mass of the exhaust gas.
Tuesday, February 12, 2013 at 3:09pm

Physics
A 0,1kg bullet is fired horizontally towards blcok A and B, which are hanging from cords. The bullet passes through block A of mass 2kg and becomes embedded in block B of mass 6.4kg. The bullet thus causes A and B to start moving with velocities of 6m,s- and 2m.s- respectively...
Tuesday, February 12, 2013 at 3:02pm

Physics
A wire of cross-sectional area 5.00x10^-6 m^2 has a resistance of 1.75 ohm. what is the resistance of a wire of the same material and length as the first wire, but with a cross-sectional area of 8.75x10^-6 m^2? I really want to understand what to do here, so detailed steps ...
Tuesday, February 12, 2013 at 2:56pm

Physics
I got 240mph by using a diagram but my lecture said i am wrong
Tuesday, February 12, 2013 at 2:21pm

Physics
What is the electrostatic force between a +1x10^-6C group of charges and another -2x10^-6 C group of charges located 0.3 m apart?
Tuesday, February 12, 2013 at 1:57pm

Physics
What is the electrostatic force between two ballons, each having 0.000005 C of charge, when they are 0.5 m apart?
Tuesday, February 12, 2013 at 1:55pm

physics
(a) A vertically polarized photon goes through two polarizing filters, the first of which is vertically aligned and the second at degrees. What is the probability that the photon is transmitted through both filters? (b) Now, you are allowed to place a polarizing filter between...
Tuesday, February 12, 2013 at 1:51pm

physics
In the double-slit experiment, consider the point at the middle of the final (detector) screen which is equidistant from the two slits. Suppose the intensity at that point is when either slit is open. Now for each of the three cases (a) bullet (b) wave (c) quantum mechanics (...
Tuesday, February 12, 2013 at 1:44pm

physics
(part 1) An athlete whirls an 8.1 kg hammer tied to the end of a 1.4 m chain in a horizontal circle. The hammer moves at the rate of 0.597 rev/s. What is the centripetal acceleration of the hammer? Assume his arm length is included in the length given for the chain. Answer in ...
Tuesday, February 12, 2013 at 1:22pm

Two blocks are connected by a lightweight, flexible cord that passes over a frictionless pulley. If m1 = 3.4 kg and m2 = 9.0 kg, and block 2 is initially at rest 140 cm above the floor, how long does it take block 2 to reach the floor?
Tuesday, February 12, 2013 at 12:30pm

Physics
A salami sandwich is dropped from the top of a 37 m tall construction crane. What is the speed of the sandwich when it is halfway to the ground? (Use conservation of energy!)
Tuesday, February 12, 2013 at 12:28pm

physics
A block of mass m1 = 3.2 kg rests on a frictionless horizontal surface. A second block of mass m2 = 1.9 kg hangs from an ideal cord of negligible mass that runs over an ideal pulley and then is connected to the first block. The blocks are released from rest a) Find the ...
Tuesday, February 12, 2013 at 12:07pm

PHYSICS
A rifle is aimed horizontally at a target 31 m away. The bullet hits the target 1.3 cm below the aiming point. Neglect air resistance. (a) What is the bullet's time of flight? s (b) What is its muzzle velocity? m/s (in the bullet's initial horizontal direction)
Tuesday, February 12, 2013 at 12:05pm

physics !!!!!!!!!!!!!
The waterfall "Angel Falls" in Venezuela is the world's tallest at h=979 m. Assume that the water's velocity on the top of the falls and on the bottom of the falls (after it hits the ground and begins to flow away) is equal, and that no total energy is lost ...
Tuesday, February 12, 2013 at 11:51am

PHYSICS
A few years ago, a movie came out about a soldier, John Carter, who was transported to Mars and could perform amazing feats of strength and jumping due to the lower Martian gravity. The surface gravity of Mars is 0.38 times that of earth. If John could lift 100 kg on earth (...
Tuesday, February 12, 2013 at 11:50am

physics!!!!!!!
In order to measure the length of a long flourescent ceiling lamp, a student makes a very small hole in a piece of paper, holds the paper above the floor, measures the distance between the hole and the floor, and finally measures the length of the light's image on the ...
Tuesday, February 12, 2013 at 11:49am

physics
what is the frequency of a citizen's band (CB) radio which has a wavelength of 11.5 meters ?
Tuesday, February 12, 2013 at 11:20am

PHYSICS
Two parallel plate capacitors are identical, except that one of them is empty and the other contains a material with a dielectric constant of 4.2 in the space between the plates. The empty capacitor is connected between the terminals of an ac generator that has a fixed ...
Tuesday, February 12, 2013 at 10:58am

Physics
During an action potential, Na^+ ions move into the cell at a rate of about 3x10^-7 mol/m^2*s. How much power must be produced by the "active Na^+ pumping" system to produce this flow against a +30-mV potential difference? Assume that the axon is 40cm long and 30um ...
Tuesday, February 12, 2013 at 1:29am

Quantum Physics
We have a qubit in the state |ψ>= √3/2 |0>+ 1/2 |1>, which we want to measure in the {Cos θ |0> + Sin θ |1>, Sin θ |0> - Cos θ |1>} basis. In order for the two possible outcomes to be equiprobable, what should be the value of...
Tuesday, February 12, 2013 at 1:22am

physics
what frequency and period would be required for sally and her hard-working partner to produce a standing wave with three nodes?
Monday, February 11, 2013 at 11:14pm

PHYSICS 2 !!!
At its normal operating speed, an electric fan motor draws only 10.9% of the current it draws when it just begins to turn the fan blade. The fan is plugged into a 120.0-V socket. What back emf does the motor generate at its normal operating speed?
Monday, February 11, 2013 at 11:08pm

PHYSICS
At its normal operating speed, an electric fan motor draws only 10.9% of the current it draws when it just begins to turn the fan blade. The fan is plugged into a 120.0-V socket. What back emf does the motor generate at its normal operating speed?
Monday, February 11, 2013 at 10:24pm

physics
A proton and an electron enter perpendicular to the direction of the magnetic field. The speed of the proton is twice the speed of the electron. What is the ratio of the force experienced by the proton to the electron?
Monday, February 11, 2013 at 9:57pm

physics
Can someone please explain to me why or how this statement is true? I don't understand it.. Two events that are simultaneous in one inertial frame of reference will not necessarily be simultaneous in any other inertial frame of reference. Thank you
Monday, February 11, 2013 at 9:38pm

physics
The wavelength of the electromagnetic waves is 200 nm. Which of following regions does it belong to? visible light region ultra violet light infrared region x-ray region
Monday, February 11, 2013 at 9:29pm

Physics
The maximum current in an AC circuit is 3.0 Amperes. What is the rms value of the current in the AC circuit? ...Thanks!
Monday, February 11, 2013 at 9:09pm

College Physics 2
A parallel-plate air capacitor is made from two plates 0.250 m square, spaced 0.70 cm apart. It is connected to a 140 V battery. a) What is the capacitance? C = 7.90×10−11 F b) What is the charge on each plate? Enter your answer as an absolute value of charge. Q = ...
Monday, February 11, 2013 at 9:09pm

Physics
Which of the following statements about emission spectra is correct? All the lines are evenly spaced. All noble gases have the same spectra. Each line corresponds to a series of wavelengths. All the lines result from discrete energy differences
Monday, February 11, 2013 at 8:47pm

Physics
A conductor of length 2m carrying a 1.5A current experiences a force of 2.2 N. What is the magnitude of the magnetic field that acts perpendicular to the flow of current in the conductor?
Monday, February 11, 2013 at 8:41pm

Physics
A freight train has a mass of 1.2 107 kg. If the locomotive can exert a constant pull of 8.4 105 N, how long does it take to increase the speed of the train from rest to 88 km/h?
Monday, February 11, 2013 at 7:55pm

If 10-kg of ice at 0 degrees Celsius is added to 2-kg of steam at 100 degrees Celsius, the temperature of the resulting mixture is? Use Joules. ANSWER: 40 Specific Heats: Ice = 2060 Steam = 2020 Latent Heats: Water melting = 3.33x10^5 Water boiling = 2.26x10^6
Monday, February 11, 2013 at 7:27pm

Physics Help
An electron with velocity v = 2.4 × 106 m/s i encounters an electric field E = 1250 N/C i. How long will it take for the speed to be one fourth its original value?
Monday, February 11, 2013 at 6:15pm

Physics Help
Charge Q is uniformly distributed around the perimeter of a semicircle of radius R. What is the electric field at the circle's center?
Monday, February 11, 2013 at 6:14pm

Physics Help
Charge is distributed uniformly along the x axis with density ßx and uniformly along the y axis with density ßy. Calculate the electric field at the points (a) r = a i + b j, and (b) r = c k.
Monday, February 11, 2013 at 6:14pm

Physics
Two blocks of lead, one twice as heavy as the other, are both at 50 degrees Celsius. The ratio of internal energy of the heavier block to that of the lighter block is? A)1:2 B)2:1 C)1:1 D)4:1
Monday, February 11, 2013 at 5:55pm

physics
A swimmer is capable of swimming at 1.4m/s in still water. Calculate the following. i. How far downstream will he land if he swims directly across 180m wide river? ii. How long will it take him to the other side.
Monday, February 11, 2013 at 5:52pm

physics
charge A has a charge of 2C, Charge B has a charge of -3C and is located 1 meter to the right of A. Charge C is located 1 meter to the right of charge B and has a charge of -1C. if a fourth charge (charge D) is placed 4 meters to the right of charge B, how much charge must it ...
Monday, February 11, 2013 at 5:42pm

Physics
Situation: While holding his rifle at shoulder-level, a 1.8 meter tall hunter accidentally discharges it straight up into the air. Questions: 1) If the bullet exits the barrel of the rifel at 200 meters per second squared, how many seconds does the hunter have to "step ...
Monday, February 11, 2013 at 5:05pm

physics
If a 0.5kg toy car is rolling down a hill with a velocity of 0.8m.s, what is the car's momentum?
Monday, February 11, 2013 at 4:31pm

physics
list and explain 5 locking devices
Monday, February 11, 2013 at 3:59pm

physics
Imagine a spring floating in space. This spring has a very small length when it is unstretched. The spring constant for this spring is 4.2 N/m. Now place 2.6 μC charges on each end of the spring, and allow it to stretch until it reaches a new equilibrium. What is the new ...
Monday, February 11, 2013 at 2:48pm

physics
A crane is used to hoist a 500kg crate vertically at a constant velocity of 4 meters per second. Ignore the effects of friction. a) calculate the magnitude of the net force experienced by the crate b) calculate the magnitude of the force applied by the cable on the crate
Monday, February 11, 2013 at 2:23pm

Physics
A car travells 20 km due north and then on a bearing of 90 degrees for 12km. Use a scale drawing.
Monday, February 11, 2013 at 1:31pm

physics
A particle with a charge of -5.0 μC and a mass of 4.3 x 10-6 kg is released from rest at point A and accelerates toward point B, arriving there with a speed of 18 m/s. The only force acting on the particle is the electric force. What is the potential difference VB - VA ...
Monday, February 11, 2013 at 1:11pm

Physics
A feather is dropped onto the surface of the moon. How far will the feather have fallen if it reaches the surface in 9.00 seconds? Given: g on moon = -1.63 meters/second2
Monday, February 11, 2013 at 12:22pm

physics
The waterfall "Angel Falls" in Venezuela is the world's tallest at h=979 m. Assume that the water's velocity on the top of the falls and on the bottom of the falls (after it hits the ground and begins to flow away) is equal, and that no total energy is lost ...
Monday, February 11, 2013 at 11:34am

physics
A few years ago, a movie came out about a soldier, John Carter, who was transported to Mars and could perform amazing feats of strength and jumping due to the lower Martian gravity. The surface gravity of Mars is 0.38 times that of earth. If John could lift 100 kg on earth (...
Monday, February 11, 2013 at 11:34am

physics!!!!!
When the distance between the hole and floor is h1=20 cm, the images's length is l1=20 cm; when the distance between the hole and floor is h2=40 cm, the images's length is l2=36 cm . What is the length L of the ceiling lamp in m?
Monday, February 11, 2013 at 11:34am

Physics
A person has a reasonable chance of surviving an automobile crash if the deceleration is no more than 30 "'s." What distance is traveled if the person is brought to rest at this rate from 115 ?
Monday, February 11, 2013 at 11:15am

Physics
A thin 5.4-m metal rod sustanins a longitudinal standing wave with vibration antinodes at each end of the rod. There are no other antinodes. The density and Young's modulus of this metal are, respectively, 5200 kg/m^3 and 7.9x10^10 N/m2. What is the frequency of the rod&#...
Monday, February 11, 2013 at 11:14am

physics
A string has a linear density of 8.1 x 10-3 kg/m and is under a tension of 200 N. The string is 2.9 m long, is fixed at both ends, and is vibrating in the standing wave pattern shown in the drawing. Determine the (a) speed, (b) wavelength, and (c) frequency of the traveling ...
Monday, February 11, 2013 at 11:03am

Physics
A lamp hangs vertically from a cord in a descending elevator with a constant deceleration a. If the tension in the cord is T0, answer the following. (Use any variable or symbol stated above along with the following as necessary: g.) (a) What is the lamp's mass? m = (b) ...
Monday, February 11, 2013 at 10:13am

physics
A basketball player can leap upward 0.69 m. What is his initial velocity at the start of the leap?
Monday, February 11, 2013 at 1:15am

physics
A car is traveling at 25m/s when an accident occurs. The car decelerates 300m/s^2 but the passenger does not slow down because he is not wearing a seatbelt. a) Supposing the distance between the passenger and the dashboard is initially 0.50m, what will be the speed of the car ...
Sunday, February 10, 2013 at 11:58pm

conceptual physics
The linear momentum of a body can be calculated by multiplying its mass by the Question 1 options: time during which the mass moves. distance the mass moves. acceleration of the mass. velocity of the mass. Save
Sunday, February 10, 2013 at 11:39pm

physics
A 80 g ice cube at 0°C is heated until 55 g has become water at 100°C and 25 g has become steam at 100°C. How much energy was added to accomplish the transformation?
Sunday, February 10, 2013 at 11:10pm

physics
In nuclear fission, a nucleus splits roughly in half. (a) What is the potential 4.00 10-14 m from a fragment that has 58 protons in it? (b) What is the potential energy in MeV of a similarly charged fragment at this distance?
Sunday, February 10, 2013 at 10:38pm

physics
In nuclear fission, a nucleus splits roughly in half. (a) What is the potential 4.00 10-14 m from a fragment that has 58 protons in it? (b) What is the potential energy in MeV of a similarly charged fragment at this distance?
Sunday, February 10, 2013 at 10:37pm

physics
The voltage across a membrane forming a cell wall is 80.0 mV and the membrane is 8.80 nm thick. What is the electric field strength? (The value is surprisingly large, but correct. Membranes are discussed in Section 19.7* of the textbook.) You may assume a uniform E-field.
Sunday, February 10, 2013 at 10:36pm

physics
The voltage across a membrane forming a cell wall is 80.0 mV and the membrane is 8.80 nm thick. What is the electric field strength? (The value is surprisingly large, but correct. Membranes are discussed in Section 19.7* of the textbook.) You may assume a uniform E-field.
Sunday, February 10, 2013 at 10:34pm

physics
The voltage across a membrane forming a cell wall is 80.0 mV and the membrane is 8.80 nm thick. What is the electric field strength? (The value is surprisingly large, but correct. Membranes are discussed in Section 19.7* of the textbook.) You may assume a uniform E-field.
Sunday, February 10, 2013 at 10:26pm

physics
If an electron travels 0.250 m from an electron gun to a TV screen in 32.0 ns, what voltage was used to accelerate it? (Note that the voltage you obtain here is lower than actually used in TVs to avoid the necessity of relativistic corrections.)
Sunday, February 10, 2013 at 10:20pm

Physics 11
A girl stands 2.5 m infront of a plane mirror. If she sees someone else 2.0 m behind her, how far is she from the image of that person?
Sunday, February 10, 2013 at 10:15pm

physics 11
A girl stands 2.5 m infront of a plane mirror. If she steps 0.5 m farther away from the mirror, how far will she be from her image?
Sunday, February 10, 2013 at 10:12pm

Physics
A jet aircraft is accelerating at 4.3 m/s2 as it climbs at an angle of è = 44° above the horizontal (see figure). What is the total force that the!@#\$%^&pit seat exerts on the 77 kg pilot?
Sunday, February 10, 2013 at 10:02pm

physics
The linear momentum of a body can be calculated by multiplying its mass by the Question 1 options: time during which the mass moves. distance the mass moves. acceleration of the mass. velocity of the mass. Save
Sunday, February 10, 2013 at 8:59pm

physics
The linear momentum of a body can be calculated by multiplying its mass by the Question 1 options: time during which the mass moves. distance the mass moves. acceleration of the mass. velocity of the mass. Save
Sunday, February 10, 2013 at 8:55pm

Physics
Rutherford, Geiger, and Marsden (his students) fired a beam of alpha particles at a gold foil. The alpha particles had an energy of about 3.6 million electron volts, a charge of +2e, and a mass of about four AMU (one Atomic Mass Unit is 1.66 x 10-27 kg. Gold has atomic number ...
Sunday, February 10, 2013 at 8:43pm

PHYSICS ASAP!!
An office window has dimensions 3.6 m by 1.6 m. As a result of the passage of a storm, the outside air pressure drops to 0.95 atm, but inside the pressure is held at 1.0 atm. What net force pushes out on the window?
Sunday, February 10, 2013 at 8:41pm

physics
A point charge of -4.00 is at the origin, and a second point charge of 6.00 is on the axis at = 0.850 . Find the magnitude and direction of the electric field at each of the following points on the axis. a) x=25.0cm b) x=1.10m c) x=-15.0cm
Sunday, February 10, 2013 at 8:40pm

Physics
Three charges are located at the corners of a rectangle as follows: Charge A: lower left corner, -3.0 Î¼C Charge B: upper left corner, -6.1 Î¼C Charge C: upper right corner, +2.7 Î¼C The distance between A and B is 0.16 m and between B ...
Sunday, February 10, 2013 at 8:40pm

Physics
As a crude model for lightning, consider the ground to be one plate of a parallel-plate capacitor and the cloud to be the other plate. The altitude of the cloud is 600m and its area is 6.5 km2. How much charge can the cloud hold before the dielectric strength of air is ...
Sunday, February 10, 2013 at 8:39pm

Physics
A positive and a negative charge are separated a distance r. What can we say about the electric potential energy of this two-particle system, according to our normal definitions of potential energy and work? Select the best answer. a. It is positive b. It is negative c. It is ...
Sunday, February 10, 2013 at 8:38pm

PHYSICS 2
A magnetic field is perpendicular to the plane of a single-turn circular coil. The magnitude of the field is changing, so that an emf of 0.98 V and a current of 2.1 A are induced in the coil. The wire is then re-formed into a single-turn square coil, which is used in the same ...
Sunday, February 10, 2013 at 8:29pm

physics
1) A car, initially traveling with a uniform velocity, accelerates at a rate of 1.0 m/s2 for a period of 12.0 seconds. If the car traveled 190.0 m during this 12.0 second period, what was the velocity of the car when it started to accelerate?
Sunday, February 10, 2013 at 7:44pm

physics
A rock is dropped from a treetop 19.6 m high, and then, 1.00 s later, a second rock is thrown down. With what initial velocity must the second rock be thrown if it is to reach the ground at the same time as the first? I'm not sure how to find the initial velocity of the ...
Sunday, February 10, 2013 at 7:00pm

physics
As your bus rounds a flat curve at constant speed, a package with mass 0.900 , suspended from the luggage compartment of the bus by a string 46.0 long, is found to hang at rest relative to the bus, with the string making an angle of 27.0with the vertical. In this position, the...
Sunday, February 10, 2013 at 6:37pm

Physics Conservation of Energy
During a rockslide, a 740 kg rock slides from rest down a hillside that is 500 m long and 300 m high. The coefficient of kinetic friction between the rock and the hill surface is 0.18. (a) If the gravitational potential energy U of the rock-Earth system is set to zero at the ...
Sunday, February 10, 2013 at 6:18pm

Physics
A container having a volume of 1 m3 holds 90 mol of helium gas at 176 ◦ C. Boltzmann’s constant is 1.38 × 10 −23 J/K. Assuming the helium behaves like an ideal gas, what is the average kinetic energy per molecule? Answer in units of J
Sunday, February 10, 2013 at 5:44pm

Physics
The drawing shows a square, each side of which has a length of L = 0.25 m. Two different positive charges q1 and q2 are fixed at the corners of the square. Find the electric potential energy of a third charge q3 = -5 x 10-9 C placed at corner A and then at corner B
Sunday, February 10, 2013 at 5:18pm

Physics Conservation of Energy
During a rockslide, a 740 kg rock slides from rest down a hillside that is 500 m long and 300 m high. The coefficient of kinetic friction between the rock and the hill surface is 0.18. (a) If the gravitational potential energy U of the rock-Earth system is set to zero at the ...
Sunday, February 10, 2013 at 5:10pm

Physics
Two identical point charges (q = +4.60 x 10-6 C) are fixed at opposite corners of a square whose sides have a length of 0.510 m. A test charge (q0 = -4.80 x 10-8 C), with a mass of 9.80 x 10-8 kg, is released from rest at one of the corners of the square. Determine the speed ...
Sunday, February 10, 2013 at 4:58pm

physics
A 1-m-tall barrel is closed on top except for a thin pipe extending 5 m up from the top. When the barrel is filled with water up to the base of the pipe ( 1 m deep ). The water pressure on the bottom of the barrel is 10 kPa. What is the pressure on the bottom when water is ...
Sunday, February 10, 2013 at 4:34pm

Ronit
What is the current through a wire if 240 coulombs of charge pass through the wire in 2.0 minutes?
Sunday, February 10, 2013 at 4:29pm

physics
A train at rest emits a sound at a frequency of 1089 Hz. An observer in a car travels away from the sound source at a speed of 30.7 m/s. What is the frequency heard by the observer? Assume the speed of sound in air to be 343 m/s.
Sunday, February 10, 2013 at 3:55pm

physics
For a certain transverse wave, the distance between two successive maxima is 1.26 m and eight maxima pass a given point along the direction of travel every 12 s. Calculate the wave speed.
Sunday, February 10, 2013 at 3:51pm

physics
A bat moving at 3.7 m/s is chasing a ﬂying insect. The bat emits a 36 kHz chirp and receives back an echo at 36.79 kHz. At what speed is the bat gaining on its prey? Take the speed of sound in air to be 340 m/s.
Sunday, February 10, 2013 at 3:50pm

PHYSICS
You drop a ball from a height of 2.8 m, and it bounces back to a height of 1.4 m. (Ignore air resistance.) (a) What fraction of its initial energy is lost during the bounce? (b) What is the ball's speed just as it leaves the ground after the bounce? m/s (c) Where did the ...
Sunday, February 10, 2013 at 3:07pm

12kg box is placed on a rough surface. A force of 20N is applied at an angle of 30 degrees. Calculate the magnitude and direction of the normal and friction forces
Sunday, February 10, 2013 at 2:51pm

Physics
Light from a sodium lamp (lambda = 589 nm) illuminates two narrow slits. The fringe spacing on a screen 150 cm behind the slits is 4.0 mm. What is the spacing b/w the two slits (in mm)?
Sunday, February 10, 2013 at 2:49pm

Physics
You run a race with your friend. At first you each have the same kinetic energy, but then you find that she is beating you. When you increase your speed by 21.0%, you are running at the same speed she is. If your mass is 77.0 kg, what is her mass?
Sunday, February 10, 2013 at 2:07pm

Physics
The three forces shown in the figure below act on a particle (with F1 = 50.0 N, F2 = 60.0 N, θ1 = 60.0°, and θ2 = 30.0°). If the particle is in translational equilibrium, find F3, the magnitude of force 3 and the angle θ3.
Sunday, February 10, 2013 at 1:30pm

Physics
boy pushes a 3.3-kg book against a vertical wall with a horizontal force of 43 N. What is the minimum coefficient of friction that will keep the book in place without sliding
Sunday, February 10, 2013 at 1:25pm

Physics
A dropping ball initial at rest is dropped 1.5m; calculate a) the traveling time of the ball and b) its velocity just before reaching the ground.
Sunday, February 10, 2013 at 12:27pm

physics
In an arcade game a 0.144 kg disk is shot across a frictionless horizontal surface by com- pressing it against a spring and releasing it. If the spring has a spring constant of 164 N/m and is compressed from its equi- librium position by 7 cm, find the speed with which the ...
Sunday, February 10, 2013 at 10:53am

physics
A 2000 watt heating element is connected in parallel to a 100 watt bulb across 200 volt source. Determine the total power and heat generated in the combination for 1.5 hours. help!
Sunday, February 10, 2013 at 3:38am

physics
If electrical energy cost 5.00 per kilowatt hour, what will be the daily cost of using a 50 watt bulb for 4 hours a day when connected across a 220 volt source?, help please!
Sunday, February 10, 2013 at 3:32am

physics
determine the amount of heat generated per minute by a 120 volt lamp which takes 0.5 amperes. thanks!
Sunday, February 10, 2013 at 3:29am

physics
State only Gauss law in integral form.Use it to find out electric field due to an isolated homogeneous sphere of charges at an outside point.
Sunday, February 10, 2013 at 1:38am

During an action potential, Na^+ ions move into the cell at a rate of about 3x10^-7 mol/m^2*s. How much power must be produced by the "active Na^+ pumping" system to produce this flow against a +30-mV potential difference? Assume that the axon is 40cm long and 30um ...
Sunday, February 10, 2013 at 1:37am

physics
2.Explain Electric field and Electronic field intensity.
Sunday, February 10, 2013 at 1:05am

Physics
A downward force of 5.1 N is exerted on a -7.3 mcirco C charge. What is the magnitude of the electric field at this point?
Saturday, February 9, 2013 at 11:55pm

physics
8. Electric field lines arising from two small charged particles P and Q. Consider the following two statements: i.The charge on P is smaller than the charge on Q. ii.The electrostatic force on P is smaller than that on Q. Which of the above statements are true? A) Only i. B) ...
Saturday, February 9, 2013 at 8:45pm

physics
A particle revolves in a horizontal circle of radius 3.20 m. At a particular instant, its acceleration is 1.20 m/s 2 in a direction that makes an angle of 55.0º to its direction of motion. Determine its speed (a) at this moment, and (b) 1.50 s later, assuming constant ...
Saturday, February 9, 2013 at 6:35pm

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