Saturday
May 18, 2013

# Homework Help: Science: Physics

Recent Homework Questions About Physics

Physics
What current is produced by a ring with a radius of 0.5 m and a uniform positive linear charge density of 1 microCoulomb/m rotatingwith an angular frequency of 4π/s? a. 1 microAmpere b. 3.14 microAmpere c. 6.28 microAmpere d. 12.6 microAmpere
Friday, March 1, 2013 at 12:23pm

Physics
Suppose that you wish to fabricate a uniform wire out of 1 g of copper. (Resistivity = 1.72*10^-8 Ohm-m, density = 8.94*10^3kg/m^3). If the wire is to have a resistance of R = 0.5 ohm and all of the copper is to be used, how long is the wire? a. 1765 m b. 1816 m c. 1.8 m d. 0....
Friday, March 1, 2013 at 12:22pm

Physics
A current of 4.00 A flows through the heating element of heater converting 500 J of electrical energy into thermal energy every second. What is the voltage across the ends of the heating element? a. 2000 V b. 125 V c. 250 V d. 0.008 V e. 0.125 V
Friday, March 1, 2013 at 12:20pm

physics
at what inclination should the object be released from rest if it is to reach a maximum horizontal distance of 2m as shown. coeff of friction is 0.37 for all surfaces of contact.
Friday, March 1, 2013 at 11:18am

physics
Find è and W in the figure below where w1 = 17.0 N, w2 = 31.0 N, and á = 67.5°, assuming that the arrangement is at rest.
Friday, March 1, 2013 at 10:17am

physics
An idealized voltmeter is connected across the terminals of a 15.0- battery, and a 72.5- appliance is also connected across its terminals. If the voltmeter reads 11.0 .
Friday, March 1, 2013 at 9:01am

physics
blue-green light has a frequency of about 6X10 to the fourth Hz. use the relationship c=fl to find the wavelength of this light in air. how does this wavelength compare with the size of the atom, which is about 10 is to ten?
Friday, March 1, 2013 at 7:11am

physics
What is the orbital radius and speed of a synchronous satellite which orbits the earth once every 24h?
Friday, March 1, 2013 at 4:42am

physics
Suppose we have two qubits in the state (a|0⟩+b|1⟩)|0⟩, to which we apply the following circuit. (a) Is the resulting state entangled? Yes No (b) Specify the state of each qubit after we applied the circuit.
Friday, March 1, 2013 at 4:07am

physics
Help me solve this physics homework: in sense we all have kinetic energy,even when we are standing still.the earth with a radius of 6.37*10power6 m,rotates about its axis once a day.ignoring the earths rotation about the sun,what is the K.E of a 50Kg man standing on the ...
Friday, March 1, 2013 at 2:14am

Physics
A projected space station consists of a circular tube that is set rotating about its center (like a tubular bicycle tire) as shown in figure below. The circle formed by the tube has a diameter of about D = 1.28km. What must be the rotation speed (in revolutions per day) if an ...
Friday, March 1, 2013 at 12:12am

PHYSICS
There is a mass at the end of a 0.6 m string, being swung around overhead at constant acceleration of(3/4)pi rad/sec^2. mass is 39.84 G. Tensile strength is 12.4 newtons need to find how many revolutions there will be before the string breaks, and the time before that happens...
Thursday, February 28, 2013 at 11:21pm

physics
The light from the sun is found to have a maximum intensity near the wave length of 470nm assuming the surface of the sun as a black body,the temperature of the sun is....
Thursday, February 28, 2013 at 10:50pm

Physics
A 1000 kg car is accelerated from rest to 100 miles/hour in 10 seconds. Find the output power of this car
Thursday, February 28, 2013 at 10:37pm

Physics
For launching a satellite into orbit around earth, would the proper conservation of energy formula be: Epi + Eki + O work = Epf + Ekf? Would work = 0 for launching a satellite? And, would Epi = -Gm1m2/radius of earth or would it just equal 0 (because we usually set Ep on earth...
Thursday, February 28, 2013 at 10:17pm

physics
In moving out of a dormitory at the end of the sememster, a student does 1.8 104 J of work. In the process, his internal energy decreases by 4.2 104 J. Determine each of the following quantities (including the algebraic sign). a) W b) U c) Q
Thursday, February 28, 2013 at 9:08pm

Physics
An automobile is brought to a stop by applying friction brakes to the wheels. The brakes get hot; their thermal energy is increased. The decrease in kinetic of the car is equal to the increase in thermal energy of the brakes. According to the first law of thermodynamics, the ...
Thursday, February 28, 2013 at 7:57pm

physics
Two point charges totaling 9.00 µC exert a repulsive force of 0.300 N on one another when separated by 0.596 m. (A) What is the charge on each? (B) What is the charge on each if the force is attractive? smallest charg
Thursday, February 28, 2013 at 7:35pm

Physics!!!!
Assume that a scale is in an elevator on the earth. What force would the scale exert on a 53 kg person standing on it when the elevator slows at 1.77 m/s2 while moving upward?
Thursday, February 28, 2013 at 7:30pm

physics
In a cloud chamber experiment, a proton enters a uniform 0.260 magnetic field directed perpendicular to its motion. You measure the proton's path on a photograph and find that it follows a circular arc of radius 6.38 . How fast was the proton moving?
Thursday, February 28, 2013 at 7:27pm

Physics
A conical pendulum is formed by attaching a 0.200kg ball to a 1.00 m-long string, then allowing the mass to move in a horizontal circle of radius 40.0cm . The figure (Figure 1) shows that the string traces out the surface of a cone, hence the name. A) What is the tension in ...
Thursday, February 28, 2013 at 6:29pm

Physics
Dry air will break down if the electric field exceeds about 3.0 × 106 V/m. What amount of charge can be placed on a capacitor if the area of each plate is 6.7 cm2?
Thursday, February 28, 2013 at 6:21pm

physics
The two plates of a capacitor hold +3200 µC and -3200 µC of charge, respectively, when the potential difference is 700 V. What is the capacitance?
Thursday, February 28, 2013 at 6:19pm

Physics
A 220g block on a 54.0cm -long string swings in a circle on a horizontal, frictionless table at 70.0 rpm. A) What is the speed of the block? m/s B) What is the tension in the string? N
Thursday, February 28, 2013 at 6:02pm

Physics
A 220g block on a 54.0cm -long string swings in a circle on a horizontal, frictionless table at 70.0 rpm. A) What is the speed of the block? m/s B) What is the tension in the string? N
Thursday, February 28, 2013 at 6:02pm

Physics
The ship in Figure P14.35 travels along a straight line parallel to the shore and a distance d = 500 m from it. The ship’s radio receives simultaneous signals of the same frequency from antennas A and B, separated by a distance L = 800 m. The signals interfere ...
Thursday, February 28, 2013 at 4:16pm

physics
Bob is driving 25 m/s and he turns a corner with a radius of 37 m. How much is Bob accelerating?
Thursday, February 28, 2013 at 3:41pm

Physics
A gold wire and a silver wire have the same dimensions. At what temperature will the silver wire have the same resistance that the gold wire has at 20°C?
Thursday, February 28, 2013 at 2:43pm

Physics
A bird stands on a bare power line carrying 2500 amps of current. 600 meters of this wire has a resistance of .009 ohms. If the bird's feet are 3 cm apart, what is the voltage difference between the bird's feet?
Thursday, February 28, 2013 at 2:43pm

Physics
(a) The current through a wire is a steady 2.5 amps. How much current passes through it between t = 0 seconds and t = 4 × 10-4 seconds? (b) The current through a wire is given by I(t) = I0e -at, where I0 = 2.5 amps and a = 6 × 103 s-1. How much electric charge ...
Thursday, February 28, 2013 at 2:42pm

physics
Two curves on a highway have the same radii. However, one is unbanked and the other is banked at an angle θ. A car can safely travel along the unbanked curve at a maximum speed v0 under conditions when the coefficient of static friction between the tires and the road is...
Thursday, February 28, 2013 at 2:27pm

physics
A kite is hovering over the ground at the end of a straight 47-m line. The tension in the line has a magnitude of 14 N. Wind blowing on the kite exerts a force of 17 N, directed 55° above the horizontal. Note that the line attached to the kite is not oriented at an angle ...
Thursday, February 28, 2013 at 2:08pm

Physics
The ship in Figure P14.35 travels along a straight line parallel to the shore and a distance d = 500 m from it. The ship’s radio receives simultaneous signals of the same frequency from antennas A and B, separated by a distance L = 800 m. The signals interfere ...
Thursday, February 28, 2013 at 1:46pm

physics
the speed of sound in water is 1500m/s how far way from an under see rock show a,b,c diver be show that he can hear is an echo
Thursday, February 28, 2013 at 11:33am

physics
when 1 g of gasoline is burned in an engine about 48 kj of heat is produced. how much mass is lost in the process? do you think this mass change could directly be measured?
Thursday, February 28, 2013 at 11:08am

physics
when 1 g of gasoline is burned in an engine about 48 kj of heat is produced. how much mass is lost in the process? do you think this mass change could directly be measured?
Thursday, February 28, 2013 at 11:08am

physics
is the work needed to bring a car's speed from 0 to 10 km/h less than, equal to ,or more than the work needed to bring its speed from 10 to 20 km/h? if the amounts of work are different ,what is the ratio between them?
Thursday, February 28, 2013 at 10:40am

physics
What do you understand by positive and negative zero?
Thursday, February 28, 2013 at 10:34am

physics
A unicorn stands atop a 34° hill. The unicorn gracefully slides down the grassy hill with ì=.16. Calculate the acceleration of the unicorn as it begins to slide down the hill. (b) If the unicorn slides for 13.9s before reaching the bottom, how far did the unicorn ...
Thursday, February 28, 2013 at 10:21am

Physics
There is a mass at the end of a 0.6 m string, being swung around overhead at constant acceleration of(3/4)pi rad/sec^2. mass is 39.84 G. need to find how many revolutions there will be before the string breaks, and the time before that happens.
Thursday, February 28, 2013 at 10:00am

physics
An MP3 player operates with a voltage of 3.7 V, and is using 0.14 W of power. Find the current being supplied by the player's battery.
Thursday, February 28, 2013 at 9:30am

physics
A dray horse is being pulled by a rope across a level plow field by a force of 750.0N exerted at an angle of 47° above the horizontal. If the horse’s velocity is constant and the coefficient of friction is ì=.21, determine the mass of the horse.
Thursday, February 28, 2013 at 9:30am

physics
A dray horse is being pulled by a rope across a level plow field by a force of 750.0N exerted at an angle of 47° above the horizontal. If the horse’s velocity is constant and the coefficient of friction is ì=.21, determine the mass of the horse.
Thursday, February 28, 2013 at 9:30am

physics
A dray horse is being pulled by a rope across a level plow field by a force of 750.0N exerted at an angle of 47° above the horizontal. If the horse’s velocity is constant and the coefficient of friction is ì=.21, determine the mass of the horse.
Thursday, February 28, 2013 at 9:30am

Physics
The Moon is about 3.8e5 km from the Earth. Find its average orbital speed about the Earth.
Thursday, February 28, 2013 at 9:21am

Physics
Calculate the speed in m/s at which Earth revolves about the Sun. You may assume the orbit is nearly circular.
Thursday, February 28, 2013 at 9:20am

physics.
A sound wave produced by a clock chime is heard 571-m away 1.1-sec later. If the clock's sound is 434-Hz, what is the sound wave's wavelength?
Thursday, February 28, 2013 at 9:06am

Physics !
The sonar of a stationary ship sends a signal with a frequency of 5.0x103-Hz through water. If the signals speed is 1.5x103-m/s and the echoes detection is 3.9-sec later. What is the depth of the water under the ship?
Thursday, February 28, 2013 at 9:05am

physics
A police car has passed by you with its siren blazing (529-Hz) while traveling at 28.1-m/s. What frequency would you hear after it has passed by?
Thursday, February 28, 2013 at 9:04am

Physics
A police car's siren has a frequency of 567-Hz while traveling at 24.8-m/s. If the car is coming toward you, and you are stationary, what frequency would you hear?
Thursday, February 28, 2013 at 9:04am

Physics
An electron is projected, with an initial speed of vi=1.10e+05 m/sec, directly towards a proton that is essentially at rest. If the electron is initially a great distance from the proton, at what distance from the proton is its speed instantaneously equal to twice its initial ...
Thursday, February 28, 2013 at 4:24am

physics
a chinook salmon
Thursday, February 28, 2013 at 4:14am

physics
a moving walkway at an airport has a speed v1 and a length l. a woman stands on the walkway as it moves while the man in a hurry to reach his flight walks on the walkway with a speed of v2 relative to the moving walkway. how long does it take the woman to travel the distance l.
Thursday, February 28, 2013 at 3:28am

physics
a river flows due east at 1.50 m/s. A boat crosses the river from the south shore to the north shore by maintaining a constant velocity of 10m/s due north relative to the water. (a) what is the velocity of the boat relative to the shore? (b) if the river is 300 m wide, how far...
Thursday, February 28, 2013 at 1:49am

physics
a soccer player kicks a rock horizontally off a 40.0-m-high cliff into a pool of water. if the player hears the sound of the splash 3.00 s later, what was the initial speed given to the rock? assume the speed of sound in air to be 343m/s.
Thursday, February 28, 2013 at 1:45am

Physics
A rock is dropped from a height of 100 meters above the ground. One second later, a ball is thrown vertically downwards, from the same height, with an initial speed of 13 m/s. How long after the ball is thrown will the two objects be at the same location above the ground?
Wednesday, February 27, 2013 at 11:59pm

Physics
A rock is dropped from a height of 100 meters above the ground. One second later, a ball is thrown vertically downwards, from the same height, with an initial speed of 13 m/s. How long after the ball is thrown will the two objects be at the same location above the ground?
Wednesday, February 27, 2013 at 11:58pm

Physics
Recently, Asteroid 2012 DA14 came within 34,200 km from the center of the earth at its point of closest approach. If the moon goes around the earth once every 27.5 days, what is the ratio of the distance of closest approach of DA14 to the radius of the orbit of the moon?
Wednesday, February 27, 2013 at 11:53pm

physics
You are the stunt director for a testosterone-laden action movie. A car drives up a ramp inclined at 10.0° above the horizontal, reaching a speed of 40.0 m/s at the end. It will jump a canyon that is 101 meters wide. The lip of the takeoff ramp is 201 meters above the ...
Wednesday, February 27, 2013 at 10:16pm

Physics
You push a block of mass m against a horizontal spring, compressing the spring a distance x. Then you release the block, and the spring sends it sliding across a tabletop. It stops a distance d from where you release it. Let k be the spring constant. What is the coefficient of...
Wednesday, February 27, 2013 at 9:18pm

Physics
A 44 kg skier starts from rest at a height of H = 18 m above the end of the ski-jump ramp. As the skier leaves the ramp, his velocity makes an angle of 28° with the horizontal. Neglect the effects of air resistance and assume the ramp is frictionless. (a) What is the ...
Wednesday, February 27, 2013 at 9:07pm

Physics
A particle is moving along the x-axis subject to the potential energy function U(x) = a(1/x) + bx2 + cx – d, where a = 6.00 J m, b = 26.0 J/m2, c = 3.00 J/m, and d = 26.0 J. Determine the x-component of the net force on the particle at the coordinate x = 3.37 m. Not sure ...
Wednesday, February 27, 2013 at 9:01pm

Physics
How long in seconds does it take for a car accelerating at 3.5m/s2 to go from rest to 120km/hr
Wednesday, February 27, 2013 at 9:00pm

Physics
In the figure below, a runaway truck with failed brakes is moving downgrade at 114 km/h just before the driver steers the truck travel up a frictionless emergency escape ramp with an inclination of 15°. The truck's mass is 5000 kg. (a) What minimum length L must the ...
Wednesday, February 27, 2013 at 8:57pm

Physics
In the figure below, a small block of mass m = 0.034 kg can slide along the frictionless loop-the-loop, with loop radius 8 cm. The block is released from rest at point P, at height h = 7R above the bottom of the loop. (For all parts, answer using g for the acceleration due to ...
Wednesday, February 27, 2013 at 8:46pm

Physics
What is the spring constant of a spring that stores 25 J of elastic potential energy when compressed by 6.0 cm from its relaxed length?
Wednesday, February 27, 2013 at 8:10pm

Physics
I'm having trouble with motion graphs. How do you go from an acceleration-time graph to a velocity-time graph or displacement time graph? I know that to go from v-t to a-t I just take the slope of the v-t graph, but how do you do it the other way around?
Wednesday, February 27, 2013 at 5:50pm

Physics
a 0.67 kg rubber ball has a speed of 2.2 m/s at point a and kinetic energy 7.1 J at point B find the total work done on the ball as it moves from a to b
Wednesday, February 27, 2013 at 5:42pm

Physics
a 0.67 kg rubber ball has a speed of 2.2 m/s at point a and kinetic energy 7.1 J at point B find the total work done on the ball as it moves from a to b
Wednesday, February 27, 2013 at 5:38pm

physics
two springs of constants 2.0*10^3 Nm and 3.0*10^3 Nm are connected in tandem, and a mass of 5.9kg hangs vertically from this spring. 1.) by what amount does the mass stretch the combined string? 2.) By what amount does the mass stretch each individual string?
Wednesday, February 27, 2013 at 5:33pm

physics
what caused a little puddle of water to appear under the syringe tip after ten minutes in the sun?
Wednesday, February 27, 2013 at 4:31pm

Physics
You have two metal spheres, one with radius 10 cm, the other 7 cm. They each possess a charge of 3 x 10-6 Coulombs. If you touch them together and let the charge come to equilibrium, how much will there be on each sphere?
Wednesday, February 27, 2013 at 4:07pm

Physics
A capacitor is made from two parallel plates separated by a distance d, and each has area A. The capacitor holds a charge Q. (a) What is the energy stored in the capacitor? (b) A mechanical force pulls the plates apart, without changing the stored charge, until they are 2d ...
Wednesday, February 27, 2013 at 4:06pm

Physics
What is the maximum charge that can be put on a conducting sphere of radius 15 cm if it is not to spark? That is, the electric field at its surface cannot exceed the dielectric strength of air. b) What is the sphere's voltage at this charge?
Wednesday, February 27, 2013 at 4:05pm

Physics
If the electric potential is given by V = (-1 volts/m4 )x2yz + (4 volts/m2)yz, find the electric field.
Wednesday, February 27, 2013 at 4:04pm

physics
A window washer pushes his scrub brush →− up a vertical window at constant speed by applying a force F as shown in Fig. P5.74. The brush weighs 15.0 N and the coefficient of kinetic friction is μk = 0.150. Calculate (a) the magnitude of →− the ...
Wednesday, February 27, 2013 at 1:47pm

Physics
A freestyle skier hits the take off ramp with an initial velocity of 17.5 m/s with a purely vertical take off (90 degrees). What is the peak height that the skier will reach? Can you fully explain to me how to get this answer? I did the formula d=Vi*deltT+(1/2)(a)(t^2). To get...
Wednesday, February 27, 2013 at 1:39pm

physics- electricity
An electric car uses a lithium metal hydride battery with a mass of 250 kg. The battery delivers 300v and holds a stored charge q of 70 ampere-hours. Calculate the total energy stored in the battery in kWh. Calculate the number of gallons of gas that would have an equivalent ...
Wednesday, February 27, 2013 at 11:37am

Physics
For a given launch velocity, at which launch angle does the projectile undergo the maximum horizontal displacement? A. 35° B. 45° C. 75° D. 80° E. 90°
Wednesday, February 27, 2013 at 10:21am

physics
what is electric power?
Wednesday, February 27, 2013 at 10:14am

physics
a 3000 pound car is parked on a hill at an angle of elevation of 16 degrees. how much force must the brakes exert to keep the car from rolling down the hill?
Wednesday, February 27, 2013 at 8:43am

PHYSICS!!!
Recently, Asteroid 2012 DA14 came within 34,200 km from the center of the earth at its point of closest approach. If the moon goes around the earth once every 27.5 days, what is the ratio of the distance of closest approach of DA14 to the radius of the orbit of the moon?
Wednesday, February 27, 2013 at 3:38am

Physics
The electric field strength @ distance = 1.0 m from a point charge is 4.0 x 10^4 N/C. What is the Electric field strength @ 2.0 m from the same charge?
Wednesday, February 27, 2013 at 3:15am

Physics
A charge-Q is located at x=-l/2 and a charge +Q is located at x=l/2 . Thus the separation between the two charges is l . The total electric field on the x axis can be written as E(x)=E(x)d^ (a) What is the direction d^ of the total electric field at any point on the x axis ...
Wednesday, February 27, 2013 at 1:47am

Physics
There are two conducting concentric hollow spheres of outer radii R2 and R1 ( R2>R1 ). The thickness of the material of both spheres is d . The inner sphere is negatively charged with charge density -σ1, . The larger sphere is positively charged with charge density +&#...
Wednesday, February 27, 2013 at 1:46am

physics
There is a very large horizontal conducting plate in the x-y plane (consider it infinitely large). Its thickness is h . The charge densities on the upper and the lower surfaces are both equal to +σ. The goal of this problem is to find the electric field (magnitude and ...
Wednesday, February 27, 2013 at 1:46am

Physics
A point charge Q1=-2µC is located at x=0, and a point charge Q2=-8µC is placed at on the x -axis of a cartesian coordinate system.The goal of this problem is to determine the electric field,E(x)=E(x)x^ , at various points along the -axis. (a)What is E(x) (in N/C) ...
Wednesday, February 27, 2013 at 1:43am

Physics
A flat thin non-conducting ring has an inner radius R1 and an outer radius R2 . The disk is uniformly charged with charge per unit area σ(>0) . (a) What is the electric field at the center, P , of the ring? Express your answer in terms of the following variables, if ...
Wednesday, February 27, 2013 at 1:42am

Physics
On the moon's surface, the force of gravity exerted by the moon on a camera is 2.4 N. What is the force of gravity exerted by the moon on the camera when it is in orbit with a radius = to twice the moon's radius?
Wednesday, February 27, 2013 at 1:23am

physics
The nuclei having same number of protons but different number of neutrons are called--------
Wednesday, February 27, 2013 at 12:35am

physics
let p and E denote the linear momentum and energy of emitted photon respectively if the wavelength of incident radiation is increased----
Wednesday, February 27, 2013 at 12:32am

physics
In the diffraction pattern due to a single slit of width d with incident ligth of wavelength lamda at and angle of diffraction thita the conditon for first minimum
Wednesday, February 27, 2013 at 12:30am

physics
The light from the sun is found to have a maximum intensity near the wavelength of 470 nm assuming the surface nof the sun a s a black body the temperature of the sun is ----------
Wednesday, February 27, 2013 at 12:23am

physics
two particles perform linear simple harmonic motionalongthe same path of length 2A and period T as shown in the graph below. the phase differe3nce between them is -------------
Wednesday, February 27, 2013 at 12:19am

physics
the number of degrees of freedom for a rigid diatomic molecule is ------------
Wednesday, February 27, 2013 at 12:17am

physics
When a transverse wave on a string is reflectred from the free end the phase change produced is-------
Wednesday, February 27, 2013 at 12:15am

physics
The buckling of a beam is found to be more is----------------
Wednesday, February 27, 2013 at 12:13am

physics
n droplets of equal sixe of radus r calesce to from a bigger drop of radius r the energy liberated is equal to ------------
Wednesday, February 27, 2013 at 12:12am

physics
The moment of inertia of thin uniform rod of mass i and length L about an axis passing through a point midway between the centre and on end perpendicular to its length is --------------
Wednesday, February 27, 2013 at 12:09am

physics
A 200 gram ball gets dropped from a roof at 15 meters high. A boy on the ground catches it. If 10 percent is translated to internal energy, then what was the increase of internal energy? Is it safe to be playing ball from the roof top?
Tuesday, February 26, 2013 at 10:53pm

Physics
A pitcher throws a baseball with a horizontal velocity of 132 ft/s (90 mph) toward home plate that is approximately 60 ft. away. What is the vertical drop of the ball when it reaches the plate? g = 32 ft/s^2.
Tuesday, February 26, 2013 at 10:27pm

Physics
A long jumper leaves the ground with an initial velocity of 12 m/s at an angle of 28-degrees above the horizontal. Determine the time of flight, the horizontal distance, and the peak height of the long-jumper.
Tuesday, February 26, 2013 at 10:22pm

Physics
Train A starts at 4 miles South of a bridge and heads North at a constant speed of 30 miles per hour. Train B starts 6 miles North of the bridge. a. What velocity must Train B have so that the two trains cross the bridge at the same time? b. If Train B goes at 35 miles per ...
Tuesday, February 26, 2013 at 10:18pm

Physics
A train is moving towards a destroyed bridge. The velocity of the train remains constant at 20 m/s. A person inside the train realizes that they will die unless they run to the back of the train and jump out. If the person is 15 m from the back of the train and the back of the...
Tuesday, February 26, 2013 at 10:16pm

Physics
At a certain instant, a ball is thrown downward with a velocity of 8.0 m/s from a height of 40 m. At the same instant, another ball is thrown upward from ground level directly in line with the first ball with a velocity of 12 m/s. Find (a) the time when the balls collide and (...
Tuesday, February 26, 2013 at 10:13pm

Physics
A horse on a merry-go-round is 20 ft from the center and travels at 10 mph. What is its angular speed?
Tuesday, February 26, 2013 at 9:29pm

physics.... please help
A ball is dropped from a height of 5.67 m. If the ball rebounds with a speed of 4.22 m/s, what is the coefficient of restitution? a. .40 b. .74 c. .56 d. 1.23 I've ruled d out because it is greater than 1.
Tuesday, February 26, 2013 at 9:20pm

Physics
One component of a magnetic field has a magnitude of 0.0445 T and points along the +x axis, while the other component has a magnitude of 0.0725 T and points along the -y axis. A particle carrying a charge of +1.01 × 10-5 C is moving along the +z axis at a speed of 4.18 &...
Tuesday, February 26, 2013 at 8:21pm

Physics
A ball is dropped from a height of 5.67 m. If the ball rebounds with a speed of 4.22 m/s, what is the coefficient of restitution? a. .40 b. .74 c. .56 d. 1.23 I've ruled d out because it is greater than 1.
Tuesday, February 26, 2013 at 7:58pm

Physics
A competitor is aiming to complete a 1500m wheel-chair race in less than 4 min. After moving at a constant speed for exactly 3.5 min, there were still 240m to go. What must his acceleration be for the remaining distance if he were to finish the race on time?
Tuesday, February 26, 2013 at 7:55pm

Physics
An 67.6 kg object moving to the right at 38.7 cm/s overtakes and collides elastically with a second 48.9 kg object moving in the same direction at 19.2 cm/s. Find the velocity of the second object after the collision. Answer in units of cm/s
Tuesday, February 26, 2013 at 7:53pm

physics
What is the KE of a 9 kg mass at 2 m/s?
Tuesday, February 26, 2013 at 7:53pm

Physics
High-speed stroboscopic photographs show that the head of a 197 g golf club is traveling at 36.8 m/s just before it strikes a 45.9 g golf ball at rest on a tee. After the collision, the club head travels (in the same direction) at 25.9 m/s. Find the speed of the golf ball ...
Tuesday, February 26, 2013 at 7:35pm

Physics
In the sport of skeleton a participant jumps onto a sled (known as a skeleton) and proceeds to slide down an icy track, belly down and head first. In the 2010 Winter Olympics, the track had sixteen turns and dropped 126 m in elevation from top to bottom. (a) In the absence of ...
Tuesday, February 26, 2013 at 7:35pm

college physics
You are in the lab with a 10 V battery. You have a 10 W light bulb and you want to put 0.75 A of current through the light bulb and 7.5 V across the light bulb. This will allow the light bulb to have a brightness proportional to 5.625 W. Assuming any resistors that you need, ...
Tuesday, February 26, 2013 at 6:20pm

College physics
According to test performed by the manufactures, an automobile with an initial speed of 75 km/h has a stopping distance of 25 m on a level road. assuming that no skidding occurs during breaking, what is the value of μ , between the wheels and the road required to achieve ...
Tuesday, February 26, 2013 at 6:16pm

physics
You are in the lab with a 10 V battery. You have a 10 W light bulb and you want to put 1/2 A of current through the light bulb and 5 V across the light bulb. This will allow the light bulb to have a brightness proportional to 2.5 W. Assuming any resistors that you need, design...
Tuesday, February 26, 2013 at 6:13pm

Physics--PLZ HELP!
When the switch is closed in a circuit, the wire between the poles of the horseshoe magnet deflects upward. From this you can conclude that the left end of the magnet is ---- -- -- -- -- -- -- A) a magnetic dipole. B) not contributing to the wire's deflection. C) a ...
Tuesday, February 26, 2013 at 5:59pm

Physics Power
1.) How much energy does a 60 W light bulb consume in 1 hour? 2.) Beth pulled her brother (m=85 kg) in a 10 kg sled with a constant force of 95 N for 100 m. a) How much work did Beth do in moving her brother? b) How much power did she expend if it took her 3 min (180 s) to ...
Tuesday, February 26, 2013 at 5:49pm

Physics
A current of 4.6 A is measured through a 7.8 ohms resistor for 1.75 minutes. How much heat is generated by the resistor?
Tuesday, February 26, 2013 at 5:41pm

Physics
A current of 4.6 A is measured through a 7.8 ohms resistor for 1.75 minutes. How much heat is generated by the resistor?
Tuesday, February 26, 2013 at 5:39pm

physics
IF A 0.5 Kg baseball(at rest) is hit by a bat with a force of 200.0 N what is the magnitude of the baseball just as it is leaving the bat?
Tuesday, February 26, 2013 at 5:23pm

Physics
In the sport of skeleton a participant jumps onto a sled (known as a skeleton) and proceeds to slide down an icy track, belly down and head first. In the 2010 Winter Olympics, the track had sixteen turns and dropped 126 m in elevation from top to bottom. (a) In the absence of ...
Tuesday, February 26, 2013 at 4:46pm

Physics
Multiple-Concept Example 13 presents useful background for this problem. The cheetah is one of the fastest accelerating animals, for it can go from rest to 34.7 m/s in 3.03 s. If its mass is 102 kg, determine the average power developed by the cheetah during the acceleration ...
Tuesday, February 26, 2013 at 3:59pm

Physics
In attempting to pass the puck to a teammate, a hockey player gives it an initial speed of 2.95 m/s. However, this speed is inadequate to compensate for the kinetic friction between the puck and the ice. As a result, the puck travels only one-half the distance between the ...
Tuesday, February 26, 2013 at 3:59pm

Physics
A student, starting from rest, slides down a water slide. On the way down, a kinetic frictional force (a nonconservative force) acts on her. The student has a mass of 78 kg, and the height of the water slide is 12.5 m. If the kinetic frictional force does -5.4 × 103 J of...
Tuesday, February 26, 2013 at 3:58pm

Physics
A small lead ball, attached to a 1.50-m rope, is being whirled in a circle that lies in the vertical plane. The ball is whirled at a constant rate of three revolutions per second and is released on the upward part of the circular motion when it is 0.75 m above the ground. The ...
Tuesday, February 26, 2013 at 3:58pm

Physics
The drawing shows a skateboarder moving at 5.40 m/s along a horizontal section of a track that is slanted upward by 48.9 ° above the horizontal at its end, which is 0.582 m above the ground. When she leaves the track, she follows the characteristic path of projectile ...
Tuesday, February 26, 2013 at 3:58pm

Physics
A bicyclist rides 2.78 km due east, while the resistive force from the air has a magnitude of 6.52 N and points due west. The rider then turns around and rides 2.78 km due west, back to her starting point. The resistive force from the air on the return trip has a magnitude of ...
Tuesday, February 26, 2013 at 3:57pm

Physics
The concepts in this problem are similar to those in Multiple-Concept Example 4, except that the force doing the work in this problem is the tension in the cable. A rescue helicopter lifts a 72.4-kg person straight up by means of a cable. The person has an upward acceleration ...
Tuesday, February 26, 2013 at 3:57pm

Physics
A person pushes a 23.5-kg shopping cart at a constant velocity for a distance of 30.3 m on a flat horizontal surface. She pushes in a direction 31.5 ° below the horizontal. A 37.3-N frictional force opposes the motion of the cart. (a) What is the magnitude of the force ...
Tuesday, February 26, 2013 at 3:56pm

physics
If a boat is being tugged by 2 tug boats 20000 newtons north, the river is flowing at 5000 newtons south what direction is the boat and what's the velocity?
Tuesday, February 26, 2013 at 3:03pm

Physics
High-speed stroboscopic photographs show that the head of a 197 g golf club is traveling at 36.8 m/s just before it strikes a 45.9 g golf ball at rest on a tee. After the collision, the club head travels (in the same direction) at 25.9 m/s. Find the speed of the golf ball ...
Tuesday, February 26, 2013 at 3:02pm

phYSICS!!!
Recently, Asteroid 2012 DA14 came within 34,200 km from the center of the earth at its point of closest approach. If the moon goes around the earth once every 27.5 days, what is the ratio of the distance of closest approach of DA14 to the radius of the orbit of the moon?
Tuesday, February 26, 2013 at 11:28am

Physics
Name the fundamental forces of nature.
Tuesday, February 26, 2013 at 11:05am

Physics
The radius of the earth is 6.37*10^6 m and its mass is 5.975*10^24 kg. Find the earth's average density to appropriate significant figure.
Tuesday, February 26, 2013 at 10:57am

Physics
The radius of the earth is 6.37*10^6 m and its mass is 5.975*10^24 kg. Find the earth's average density to appropriate significant figure.
Tuesday, February 26, 2013 at 10:49am

Physics
The radius of the earth is 6.37*10^6 m and its mass is 5.975*10^24 kg. Find the earth's average density to appropriate significant figure.
Tuesday, February 26, 2013 at 10:48am

Physics
The radius of the earth is 6.37*10^6 m and its mass is 5.975*10^24 kg. Find the earth's average density to appropriate significant figure.
Tuesday, February 26, 2013 at 10:48am

physics
an infinite ladder network of resistance is constructed with 1 ohm and 2 ohm resistances .calculate equivalent resistance between points a and b
Tuesday, February 26, 2013 at 10:46am

Physics
One of the most powerful cranes in the world, operating in Switzerland, can slowly raise a load of 6000 tonne to a height of 12 m. (1 tonne = 1000 kg) The acceleration of gravity is 9.81 m/s2 . How much work is done by the crane? Answer in units of MJ I found it by using Work...
Tuesday, February 26, 2013 at 10:03am

Physics
A 64.7 kg astronaut is on a space walk away from the shuttle when her tether line breaks. She is able to throw her 14.1 kg oxygen tank away from the shuttle with a speed of 7.45m/s to propel herself back to the shuttle. Assuming that she starts from rest (rela- tive to the ...
Tuesday, February 26, 2013 at 9:32am

Physics true false
true false The speed of a particle is always positive. True False The average speed of a particle is equal to the magnitude of its average velocity. True False The acceleration of a particle can be non-zero when its speed is constant. True False When the average velocity of a ...
Tuesday, February 26, 2013 at 9:07am

physics
the moment of inertia of a thin uniform rod of mass M and length L about an axis passing through a point midway between the centre and one end perpendicular to its length is -----------------------------------
Tuesday, February 26, 2013 at 8:33am

physics
motor A lift a steel bar 5000N upward at a constant 2m/s. motor B lift 4000N steel bar upward at a constant 3m/s. which motor is supplying more power?
Tuesday, February 26, 2013 at 8:12am

Physics
A spherical concave mirror has a raduis of curvature of 6.0 cm. At what distance from the mirror should a 6.0 cm object be placed to obtain an image that is 48 cm tall?
Tuesday, February 26, 2013 at 7:54am

PHYSICS 1 ..'''''''''''''''''''''''' helllpppppppp
A girl of mass (Mg) is standing on a plank of mass (Mp). Both are originally at rest on a frozen lake that constitutes a frictionless, flat surface. The girl begins to walk along the plank at a constant velocity (vgp) to the right relative to the plank. (The subscript gp ...
Tuesday, February 26, 2013 at 2:00am

physics
A canon mounted on a pirate ship fires a cannonball at 125 m/s horizontally, at a height of 17.5m above the ocean surface. Ignore air resistance. (a) How much time elapses until it splashes into the water? (b) How far from the ship does it land?
Tuesday, February 26, 2013 at 12:02am

Physics
I'm trying to rank the maximum temperatures of water at 20 degrees Celsius after adding in heated copper cylinders. The first case is 1 cylinder at 22.5 degrees Celsius. Second is two cylinders at 25 degrees Celsius. Third is 3 cylinders at 25 degrees Celsius. Lastly, 1 ...
Tuesday, February 26, 2013 at 12:01am

physics
The infamous German "Paris gun" was used to launch a projectile with a flight time of 170 s for a horizontal distance of 122 km. Based on this information, and ignoring air resistance , calculate (a) the gun's muzzle speed and (b) the angle, measured above the ...
Monday, February 25, 2013 at 11:40pm

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