Homework Help: Science: Physics

Recent Homework Questions About Physics

Physics
Camera lenses are described in terms of their focal length. A 50.0 mm lens has a focal length of 50.0 mm (a) A camera with a 50 mm lens is focused on an object 4.0 m away. Locate the image. (b) A 980 mm lens is focused on an object 125 m away. Locate the image.
Tuesday, May 21, 2013 at 9:13pm

physics
If a metal wire carries a current of 79 . 0 mA, how long does it take for 7.90 × 10 20 electrons to pass a given cross-sectional area anywhere along the wire? The fundamental charge is 1 . 602 × 10 − 19 C. Answer in units of s
Tuesday, May 21, 2013 at 7:24pm

physics
A man leaves his house and begins to walk for 2 hours. After walking in a straight line for two hours he is 10 miles from home. Calculate the man's average speed on terms of miles per hour.
Tuesday, May 21, 2013 at 7:24pm

physics
How am I supposed to answer this question on the lab write-up? I have the date, but I don't know the formula or process to use. Thanks. Organizing Data: Using your estimate of the threshold frequency from your first data table and your measured value of ft for sodium from ...
Tuesday, May 21, 2013 at 7:16pm

physics
A Martian rover is moving up a hill sloped at 30.0° with the horizontal. If it has a constant velocity of 1.50 meters/second, calculate its vertical displacement after 21.0 seconds
Tuesday, May 21, 2013 at 3:42pm

physics
Use the Biot Savart law to compute the magnetic field at the center of a metallic ring. the ring has a radius of 10^-6 m and is connected to two infinite wires. the current in the wires is 1 amp. the ring is lying in the [x,y,z= 0 ] plane. the first wire is attached to the ...
Tuesday, May 21, 2013 at 12:32pm

Physics
What are the components of a vector with a magnitude of 4.00 and a direction of -122 degrees?
Tuesday, May 21, 2013 at 11:58am

Physics
A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long in seconds does it take for the door to fully...
Tuesday, May 21, 2013 at 11:53am

Physics
In a city grid, each block o the east-west streets is 180 meters long. Each block on the north-south streets is also 180 meters long. A walker walks 4 blocks north and then 3 blocks east. How much father did the walker travel than the actual distance between the start and end ...
Tuesday, May 21, 2013 at 11:38am

physics
A package weighing 75 N is sitting on a coffee table. The package is cubic with edges of 10 cm. How much pressure does the package exert on the table?
Tuesday, May 21, 2013 at 10:15am

physics
An object in static equilibrium has a coefficient of static friction as 0.110. If the normal force acting on the object is 95.0 newtons, what is the mass of the object?
Tuesday, May 21, 2013 at 9:54am

physics
An automobile and train move together along parallel paths at 28.8 m/s. The automobile then undergoes a uniform acceleration of −4 m/s 2 because of a red light and comes to rest. It remains at rest for 63.8 s, then accelerates back to a speed of 28.8 m/s at a rate of 1....
Tuesday, May 21, 2013 at 8:13am

physics
a body is moving with uniform acceleration of 10m/s2.if it starts from rest calculate its displacement after 5s
Tuesday, May 21, 2013 at 8:07am

physics
(c) A ladder with length L and mass m rests against a wall. Its upper end is a distance h above the ground (Figure 13.3). The center of gravity of the ladder is one-third of the way up the ladder. A fire fighter with mass M climbs halfway up the ladder. Assume that the wall, ...
Tuesday, May 21, 2013 at 1:45am

Physics
How much mechanical energy was lost during the ball's fall?
Monday, May 20, 2013 at 11:42pm

physics
A tennis ball with a speed of 12.5 m/s is moving perpendicular to a wall. After striking the wall, the ball rebounds in the opposite direction with a speed of 11.4 m/s. If the ball is in contact with the wall for 0.0139 s, what is the average acceleration of the ball while it ...
Monday, May 20, 2013 at 10:56pm

physics
An automobile and train move together along parallel paths at 20.3 m/s. The automobile then undergoes a uniform acceleration of −4 m/s2 because of a red light and comes to rest. It remains at rest for 19.4 s, then accelerates back to a speed of 20.3 m/s at a rate of 1.95...
Monday, May 20, 2013 at 10:55pm

Physics
A pair of eyeglasses is designed to allow a person with a far-point distance of 2.06 to read a road sign at a distance of 20.6. Find the focal length required of these glasses if they are to be worn 2.50 from the eyes.
Monday, May 20, 2013 at 10:47pm

Physics
Take an average 82 kg pet frog, what's it weight on earth? What is it's weight on the moon?
Monday, May 20, 2013 at 8:32pm

Physics
The answer is in parenthesis, but I just don't get it. 11. The large window air conditioner in Anita Breeze's room draws 11 amps of current. Determine the quantity of charge that will pass through Anita's window AC in the next 10 minutes. (6600 C)
Monday, May 20, 2013 at 8:14pm

Physics
A myopic student is shaving without his glasses. If his eyes have a far point of 1.5, what is the greatest distance he can stand from the mirror and still see his image clearly?
Monday, May 20, 2013 at 6:56pm

physics
An 80 kg crate was slowed to a stop when a frictional force of 160 Newtons was applied. It was originally traveling at 5.5 m/s. What distance did the box travel before it came to a stop? m. Round to first decimal.
Monday, May 20, 2013 at 6:14pm

Physics
Two blocks are in contact on a frictionless table. A horizontal force F is applied to M2, as shown. If M1 = 1.06 kg, M2 = 3.80 kg, and F = 4.85 N, find the size of the contact force between the two blocks. If instead an equal but oppositely directed force is applied to M1 ...
Monday, May 20, 2013 at 5:47pm

Applied Physics
An anchor holding a boat stationary on a river forms a 65 degree angle with the river bottom. The anchor line is 40 meters long. Assuming the river has a uniform depth, how deep is the river directly below the boat?
Monday, May 20, 2013 at 4:20pm

physics
An athlete is running at a constant velocity with a javelin held in his right hand. The force he is applying on the javelin as he carries it is 5.0 newtons. If he covers a distance of 10 meters, what work has he done on the javelin?
Monday, May 20, 2013 at 4:04pm

physics
How many calories of heat must be added to 455 g of steel to raise its temperature from 20 °C to 192 °C? (Note: csteel = 0.115 cal./g. °C.)
Monday, May 20, 2013 at 3:58pm

physics
A mechanic lifts the front of a car with a jack. Find the mechanical advantage if a force of 30.0 lb on the jack handle lifts the car that weighs 960 lb
Monday, May 20, 2013 at 3:54pm

physics
An electron is accelerated from rest by a uniform electric field of 3310V/M that is vertically pointing up, if the electron is traveling 6200000m/s how far (m) has it traveled in the electric field?
Monday, May 20, 2013 at 2:56pm

physics
A biker rides on an upward-sloped road inclined at a 15.0° angle with the horizontal. If he moves at a constant speed of 2.0 meters/second for 60 seconds, what is the magnitude of his horizontal displacement?
Monday, May 20, 2013 at 2:20pm

physics
A rigid tank contains 38:0 kg of O2 gas at a pressure of 9:70 atm. If the oxygen is replaced by helium, how many kilogram of helium will be needed to produce a pressure of 8:00 atm?
Monday, May 20, 2013 at 12:43pm

Physics
A wheel and axle arrangement has an axle with a diameter of 25cm. A rope is wrapped around the axle and is supporting a load of 2 tonnes. 1)If the mechanical advantage of the system is 30, determine the diameter of the wheel. ANSWER = m 2)Determine the effort required to ...
Monday, May 20, 2013 at 12:16pm

Physics
How long (in seconds) would it take a sound to travel underwater across the San Francisco Bay at its widest point of 19 000 meters?
Monday, May 20, 2013 at 11:38am

physics
Root x +x square=y
Monday, May 20, 2013 at 11:17am

physics
Root x +x square=y
Monday, May 20, 2013 at 11:13am

Physics
A mass m is attached to a weightless string of length L, cross section S, and tensile strength ( the maximum tension it can withstand ) T . The mass is suddenly released from a point near the fixed end of the string. What condition should be on the value of Young's modulus...
Monday, May 20, 2013 at 8:16am

physics
if The magnitude of the nuclear spinangular momentum of a nuclei is 15 /2 units. Then what will be the value of I
Monday, May 20, 2013 at 6:02am

heeeeeeeeeeeeeelp Physics
A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long in seconds does it take for the door to fully...
Monday, May 20, 2013 at 5:35am

Physics
I(mass:80kg) sit down in the center of a trampoline and the surface sinks down by a distance of 10 cm when I reach equilibrium. How far above the ground in m must the trampoline be placed so that if I jump onto the trampoline from a height of 3 m above the surface of the ...
Monday, May 20, 2013 at 4:02am

Physics..Elena or anybody please help
I(mass=80 kg) sit down in the center of a trampoline and the surface sinks down by a distance of 10 cm when I reach equilibrium. How far above the ground in m must the trampoline be placed so that if I jump onto the trampoline from a height of 3 m above the surface of the ...
Monday, May 20, 2013 at 3:16am

Physics
A lady applies makeup using a concave mirror with a focal length of 10 cm. At a distance of 6 cm from the mirror, how large does her 4 cm wide eye appear? Solve mathematically
Monday, May 20, 2013 at 3:00am

physics
You're quietly sitting by a street one day, enjoying the sun, when you notice a speeding car traveling at 20 m/s down the street. The driver notices that there's a stop sign in the street and hits the brakes 40 m before the stop sign, coming to a stop right at the ...
Monday, May 20, 2013 at 2:59am

Science
The galaxies in the universe are all flying away from each other. The speeds of nearby galaxies are proportional to the distance the galaxy is away from us. This relation, v=Hd is known as Hubble's law and the constant H is known as Hubble's constant. The evolution of ...
Monday, May 20, 2013 at 1:17am

physics
Find the tension T2 of the box hanging from the rope if 1 = 25°, 2 = 65°, T1 = 60.58 newtons, and W = 143.4 newtons answer please
Sunday, May 19, 2013 at 11:28pm

physics
How long does it take light to travel through a 2.7 mm-thick piece of window glass?
Sunday, May 19, 2013 at 10:00pm

Physics
A load W=2 kN is applied vertically to joint C of truss ABCDE as indicated. You will use the method of joints to obtain the axial forces in the bars and reactions at the supports A, E . We start with the classification of the degrees of freedom as "free" or "...
Sunday, May 19, 2013 at 9:14pm

PHYSICS
The object of the long jump is to launch oneself as a projectile and attain the maximum horizontal range (Fig. 3–26). Here we shall treat the long jumper as a particle even though the human body is fairly large compared to the size of the trajectory. Actually there is one...
Sunday, May 19, 2013 at 9:05pm

Applied Physics
A 22g bullet is fired at a muzzel velocity of 509m/s from an 8.75 kg gun with a barrel 72cm long. the force on the bullet while it is in the barrel is about?
Sunday, May 19, 2013 at 8:52pm

PhySics
Using several bags filled with different amounts of the same item, take the mass of each and develop a procedure to determine the mass of a single item. (modelling milikan's oil drop experiment)
Sunday, May 19, 2013 at 8:41pm

physics
A football is kicked with a velocity of 31 m/s at an angle of 41. What is the ball's acceleration in the vertical direction as it flies through the air?
Sunday, May 19, 2013 at 8:31pm

physics
Three wires are arranged in an equilateral triangle as shown in the figure below. The lower two wires are 4.00 apart. Assume all the wires are 1.35 long for this problem (extending into the screen).
Sunday, May 19, 2013 at 4:28pm

physics
a pair of parallel plates is charge by a 30.3V battery, if the field between the plates is 1050N/C how far apart are the plates? answer in meters
Sunday, May 19, 2013 at 4:00pm

physics
If the electrical field due to a point charge is .000602N/C what is the magnitude of the field (N/C)3.51 times as far away?
Sunday, May 19, 2013 at 3:48pm

physics
Two uniform 81.6 g marbles 1.81 cm in diameter are stacked in a container that is 2.78 cm wide. 1) Find the force that the container exerts on the marble at the point of contact A, B and C. 2) What force does each marble exert on the other?
Sunday, May 19, 2013 at 3:01pm

Physics HELPPP PLEASEEE
A 0.60 kg sphere rotates around a vertical shaft supported by two strings, as shown. If the tension in the upper string is 18 N. Calculate the tension in the lower string? the rotation rate (in rev/min) of the system?
Sunday, May 19, 2013 at 2:41pm

Physics
A race car starts from rest in the pit area and accelerates at a uniform rate to a speed of 35 m/s in 11s, moving on a circular track of radius 500 m. Determine the tangential and centripetal components of the net force excreted on the car(by the ground) when it's speed is...
Sunday, May 19, 2013 at 1:32pm

physics
A ball of mass 8kg falls from rest from a height of100m neglecting air resistance calculate.its total enegy after falling a distance of 400.
Sunday, May 19, 2013 at 12:16pm

physics
A gas at 273 kelvin expands by 0.1 cubic metre if it is heated through 50 kelvin. Calculate the original volume at constant pressure
Sunday, May 19, 2013 at 11:14am

Physics
A system consisting of two fixed and two movable pulleys has a mechanical advantage of 4.00. If a force of 124 N is exerted, which weight can be raised?
Sunday, May 19, 2013 at 12:41am

physics
I need help devloping a procedure: Using several bags filled with different amounts of the same item, take the mass of each and develop (and enact) a procedure to determine the mass of a single item....This procedure is supposed to model Milikans oil drop experiement.
Saturday, May 18, 2013 at 11:45pm

physics
In a string instrument.If I pluck the same string at different places,will the frequencies be the same?Can someone explain it to me?
Saturday, May 18, 2013 at 10:39pm

Physics
Three objects are connected on an inclined table as shown in the diagram below. The objects have masses 8.0 kg, 4.0 kg and 2.0 kg as shown, and the pulleys are frictionless. The tabletop is rough, with a coefficient of kinetic friction of 0.47, and makes an angle of 20.0° ...
Saturday, May 18, 2013 at 9:29pm

Physics 1
(I) determine the tangential and centripetal components of the net force excreted on the car(by the ground) when it accelerates at a uniform speed of 15 m/s in 11 s, moving on a circular track of radius 500m. The cars mass is 1100kg.
Saturday, May 18, 2013 at 8:37pm

Physics
An arrow is fired horizontally from the top of a 40.0-m vertical cliff and lands 125 m away. Therefore the arrow was fired at _____ m/s.
Saturday, May 18, 2013 at 6:51pm

Physics
The radius of planet X is 5.0 bleems. It takes 4 earth years to complete it's orbit. Another planet, Z, orbits the same sun and has an orbit with the radius of 12 bleems. How long does it take for planet Z to complete an orbit?
Saturday, May 18, 2013 at 5:09pm

physics
A hollow steel shaft has an external diameter of 120 mm and is 10 mm thick. It is coupled to a solid shaft of the same material, 100 mm in diameter. If the length of the hollow shaft is 960 mm, find the length of the solid shaft, so that the total angle of twist is limited to ...
Saturday, May 18, 2013 at 1:43pm

physics
The speed of a moving bullet can be determined by allowing the bullet to pass through two rotating paper disks mounted a distance d apart on the same axle (Fig. below). From the angular displacement of the two bullet holes in the disks and the rotational speed of the disks, we...
Saturday, May 18, 2013 at 12:17pm

physics
A rod of length 30.0 cm has linear density (mass-per-length) given by lambda = 50.0 g/m + 20.0 y g/m2 , where y is the distance from one end, measured in meters. (a) What is the mass of the rod? (b) How far from the y = 0 end is its center of mass?
Saturday, May 18, 2013 at 12:15pm

physics
explain the law of motion needed to slove this problem. On Planet Zorg, a 30kg barbell can be lifted by only exerting a force of 180N. what is the acceleration of gravity on Planet Zorg? Predict how the motion of this object would change on earth.
Saturday, May 18, 2013 at 10:37am

physics
¬Calculate the period of oscillation of a simple pendulum of length 1.8 m, with a bob of mass 2.2 kg. What assumption is made in this calculation? (g = 9.8 m s - 2) If the bob of this pendulum is pulled aside a horizontal distance of 20cm and released, what will be the ...
Saturday, May 18, 2013 at 5:48am

Physics
2 factors that increase static friction? Could it be weight or the ground?
Saturday, May 18, 2013 at 5:06am

Physics Please Help
A point charge of charge 1 mC and mass 100 g is attached to a non-conducting massless rod of length 10 cm. The other end of the rod is attached to a two-dimensional sheet with uniform charge density σ and the rod is free to rotate. The sheet is parallel to the y-z plane (...
Saturday, May 18, 2013 at 3:37am

physics
Marks: 1 A car merges onto the highway from rest in 10 seconds. The final speed of the car is 60 mph. Estimate the acceleration of the car.
Saturday, May 18, 2013 at 1:10am

Physics
If the same shoe were dropped from a height of 40m, how many seconds would it take it to hit the floor?
Friday, May 17, 2013 at 3:56pm

World History
1. The purpose of American and European imperialism in the Pacific was mainly to gain. A. markets fro manufactured products B. coaling stations and naval bases C. sources of raw materials D. places for surplus population I said C. 2. The development of antiseptics during the ...
Friday, May 17, 2013 at 3:39pm

Physics
A circular plate of radius 0.5 m is placed perpendicular to the direction of the magnetic field of 0.5 Tesla. What is the change of flux in the plate if it rotates and its plane becomes parallel to the direction of the magnetic field?
Friday, May 17, 2013 at 2:08pm

physics
In a city grid, each block on the east-west streets is 100 meters long. Each block on the north-south streets is 20 meters long. A walker walks 4 blocks west and then 4 blocks south. How much father did the walker travel than the actual distance between the start and end ...
Friday, May 17, 2013 at 10:45am

physics
Q 4_1? 4_2? 4_3? plz help.
Friday, May 17, 2013 at 9:16am

physics
One day I decide I want to see how high I can throw a rock. I throw a rock straight up in the air and it has a speed of 30 m/s when it leaves my hand. I then realize this was foolish, as I need to get out of the way before the rock comes back down and hits me on the head. How ...
Friday, May 17, 2013 at 6:40am

physics
Two point charges +q=1 μC and −q=−1 μC with mass m=1 g are fixed at the positions ±r⃗ 0 with |r0|=1 m. The charges are released from rest at t=0. Find the time τ in seconds at which they collide. Hint: Can you do it without integrating ...
Friday, May 17, 2013 at 6:39am

Physics
A ball is fastened to one en of a 28 cm string, and the other end is held fixed to a support. The ball whirls in a horizontal circle. Find the speed of the ball in its circular path if the string makes an angle of 35 degrees to the vertical.
Thursday, May 16, 2013 at 10:50pm

physics
A load W=2 kN is applied vertically to joint C of truss ABCDE as indicated. You will use the method of joints to obtain the axial forces in the bars and reactions at the supports A, E .
Thursday, May 16, 2013 at 9:36pm

Physics
From a height of 30.5 , a 1.45 bird dives (from rest) into a small fish tank containing 49.0 of water. What is the maximum rise in temperature of the water if the bird gives it all of its mechanical energy?
Thursday, May 16, 2013 at 9:30pm

physics
A human cannonball is launched from a cannon at 26.4 m/s at 20.4 degrees above the horizontal. (Assume he/she lands in a net the same height as the cannon.) How high in the air does he/she go?
Thursday, May 16, 2013 at 7:48pm

Physics
Two point charges +q=1 ìC and −q=−1 ìC with mass m=1 g are fixed at the positions ±r ⃗ 0 with |r 0 |=1 m . The charges are released from rest at t=0 . Find the time ô in seconds at which they collide.
Thursday, May 16, 2013 at 7:17pm

Physics, Capacitance
What would be the capacitance of a ball the size of the sun, if a conducting material covered its entire surface (radius, R = 7108 m)?
Thursday, May 16, 2013 at 3:21pm

physics
A car with a mass of 1000kg is travelling at a constant velocity. The force from the engine is 200Newtons. Calculate the acceleration of the car using the formula f=ma. How long will it take this car to travel 0-60 mph (n.b. 1mph = 0.45m/s)
Thursday, May 16, 2013 at 2:40pm

physics
a 75-kilogram bicylcist coasts down a hill at a constant speed of 12 meters per second. what is the kinetic energyof the bicyclist?
Thursday, May 16, 2013 at 1:42pm

physics(HELP..)
A diatomic ideal gas is heated at constant volume until its pressure becomes 3 times.it is again heated at constant pressure until its volume is doubled.find the molar heat capacity for the whole process?
Thursday, May 16, 2013 at 3:49am

physics
A diatomic ideal gas is heated at constant volume until its pressure becomes 3 times.it is again heated at constant pressure until its volume is doubled.find the molar heat capacity for the whole process?
Thursday, May 16, 2013 at 3:49am

Physics
If the EMF produced in a wire is 0.88 volts and the wire moves perpendicular to a magnetic field of strength 0.075 newtons/amp·meter at a speed of 4.20 meters/second, what is the length of the wire in the magnetic field?
Thursday, May 16, 2013 at 1:22am

Physics
A frog is jumping around its pond. At some time t , the frog is in mid-jump and has a kinetic energy of 1 J and a momentum of magnitude 0.5 kg⋅m/s . What is the mass of the frog in kg?
Wednesday, May 15, 2013 at 11:05pm

physics 11
a 4.00kg object traveling westward at 25.0m/s hits a 15.0kg object at rest. the 4.00kg object bounces eastward at 8.00m/s. what is the speed and direction of the 15.0kg object?
Wednesday, May 15, 2013 at 6:34pm

Physics
An open organ pipe of length 0.744411 m and a closed one of length 1.10545 m are sounded together. What beat frequency is generated by the first overtone of the closed pipe with the fundamental of the open pipe? The speed of sound is 340 m/s. Answer in units of Hz
Wednesday, May 15, 2013 at 4:39pm

Physics
When two tuning forks are stuck simultaneously, 3 beats per second are heard. The frequency of one fork is 510 Hz. A piece of wax is placed on the 510 Hz fork to lower its frequency slightly. If the beat frequency is increased, what is the correct frequency for the second fork...
Wednesday, May 15, 2013 at 4:38pm

physics
A runner dashes from the starting line (x=0) to a point 108 m away and then turns around and runs to a point 19 m away from the starting point in 23.4 seconds. To the nearest tenth of a m/s what is the average speed?
Wednesday, May 15, 2013 at 3:15pm

Physics
Jemima is sanding some floorboards with an electric sander which has a power rating of 360W. Jemima has the sander on for 45 minutes. The Sander is only 55% efficient. The electricity supplier charges 14.8p per kWh. What will be the cost of the 'wasted' energy? I know ...
Wednesday, May 15, 2013 at 1:21pm

physics
two lead spheres whose diameters are 20 cm and 2 cm are placed with centres 100 cm apart. Calculate the force of gravitation between them.(density of lead =11500 kg/m^3
Wednesday, May 15, 2013 at 10:02am

physics/chemistry(Thermodynamics)!!!!!helppppp!
In a certain chemical process,a lab technician supplies 254 j of heat to a system. At the same time,73 j of work are done on the system by iys surroundings.What is the increase in the internal energy of the system?
Wednesday, May 15, 2013 at 9:57am

Physics
A point charge of charge 1 mC and mass 100 g is attached to a non-conducting massless rod of length 10 cm. The other end of the rod is attached to a two-dimensional sheet with uniform charge density σ and the rod is free to rotate. The sheet is parallel to the y-z plane (...
Wednesday, May 15, 2013 at 5:33am

science-physics
A worker sits at one end of a 183-N uniform rod that is 2.80 m long. A weight of 107 N is placed at the other end of the rod. The rod is balanced when the pivot is 0.670 m from the worker. Calculate the weight of the worker
Wednesday, May 15, 2013 at 1:51am

Physics
How long is the sound wave if frequency is 320 Hz? Speed of sound =340 m/s
Wednesday, May 15, 2013 at 12:05am

physics
An organ pipe is 84 cm long and at a temperature of 20 degrees C. What is the fundamental (in Hertz) if the pipe is closed at one end thanks!
Tuesday, May 14, 2013 at 10:31pm

physics
A guitar string is 92 cm long and has a mass of 3.7 g. The length L from the bridge to the support post is 65 cm, and the string is under a tension of 570 N. What is the frequency of the fundamental tone thanks!
Tuesday, May 14, 2013 at 9:45pm

PHYSICS/CHEMISTRY
Can someone explain to me, what does Metastable isotope means? I already read the definitions on the internet but I really don't understand it. Thanks in advance.
Tuesday, May 14, 2013 at 9:22pm

physics
Two point charges +q=1 μC and −q=−1 μC with mass m=1 g are fixed at the positions ±r ⃗ 0 with |r 0|=1 m. The charges are released from rest at t=0. Find the time τ in seconds at which they collide.
Tuesday, May 14, 2013 at 9:03pm

physics
thus far in the course we have ignored that on the earths surface an object must have a slightly unbalanced force to rotate with the earth, pretending that the normal force precisely balances the objects weight. A student with a mass of 65.0kg stands at the equator. The radius...
Tuesday, May 14, 2013 at 8:05pm

physics
the space shuttle typically orbits 400 km above the earths surface. The earth has a mass of 5.98 * 10^24 kg and a radius of 6380km. A) How much would a 2000 kg part for the space station weigh when it has been lifted to that orbit in the shuttles cargo bay? B)Use your result ...
Tuesday, May 14, 2013 at 7:54pm

physics
A person takes a trip, driving with a constant speed of 92.5 km/h except for a 20.0 min rest stop. If the person's average speed is 71.2 km/h, how much time is spent on the trip and how far does the person travel?
Tuesday, May 14, 2013 at 7:49pm

Physics
A roller coaster has a mass of 425 kg. It sits at the top of a hill with height 66 m. If it drops from this hill, how fast is it going when it reaches the bottom? (Assume there is no air resistance or friction.)
Tuesday, May 14, 2013 at 4:40pm

physics
The convex lens of a copy machine has a focal length of 22.0 cm. A letter to be copied is placed 37.0 cm from the lens. (a) How far from the lens is the copy paper? (b) How much larger will the copy be?
Tuesday, May 14, 2013 at 3:23pm

physics
In order to clearly read a book 16 cm away, a farsighted girl needs an image to be 36 cm from her eyes. What focal length is needed for the lens in her eyeglasses?
Tuesday, May 14, 2013 at 3:22pm

physics
Camera lenses are described in terms of their focal length. A 50.0 mm lens has a focal length of 50.0 mm. (a) A camera with a 50 mm lens is focused on an object 4.0 m away. Locate the image. (b) A 980 mm lens is focused on an object 125 m away. Locate the image.
Tuesday, May 14, 2013 at 3:22pm

physics
A convex lens is needed to produce an image that is 0.70 times the size of the object and located 28 cm from the lens on the other side. What focal length should be specified?
Tuesday, May 14, 2013 at 3:22pm

physics
The speed of light in a certain piece of clear plastic is 1.95 108 m/s. A ray of light strikes the plastic at an angle of 21°. At what angle is the ray refracted?
Tuesday, May 14, 2013 at 3:21pm

physics
A ray of light in a tank of water has an angle of incidence of 23°. What is the angle of refraction in air? (Enter 0 if total internal reflection occurs.)
Tuesday, May 14, 2013 at 3:21pm

physics
he index of refraction of crown glass is 1.53 for violet light, and it is 1.51 for red light. (a) What is the speed of violet light in crown glass? (b) What is the speed of red light in crown glass?
Tuesday, May 14, 2013 at 3:20pm

physics
A diamond's index of refraction for red light, 656 nm, is 2.410, while that for blue light, 434 nm, is 2.450. Suppose white light is incident on the diamond at 32.2°. Find the angles of refraction for red and blue light. red light? blue light?
Tuesday, May 14, 2013 at 3:20pm

physics
A thick sheet of plastic, n = 1.500, is used as the side of an aquarium tank. Light reflected from a fish in the water has an angle of incidence of 30.0°. At what angle does the light enter the air?
Tuesday, May 14, 2013 at 3:19pm

physics
A beam of light strikes the flat, glass side of a water-filled aquarium at an angle of 37.5° to the normal. For glass, n = 1.50. (a) At what angle does the beam enter the glass? (b) At what angle does the beam enter the water?
Tuesday, May 14, 2013 at 3:19pm

Physics
The truss structure ABCD is loaded with a concentrated force P = 2 kN applied at a 45° angle at joint D as indicated in the figure. All bars in the truss have equal cross sectional area and are made of the same homogeneous linear elastic material. The dimensions are H=3 m ...
Tuesday, May 14, 2013 at 1:23pm

physics
A 12 g bullet is stopped in a block of wood (mw = 5.9 kg). The speed of the bullet- plus-wood combination immediately after the collision is 0.95 m/s. What was the original speed of the bullet? Answer in units of m/s
Tuesday, May 14, 2013 at 1:19pm

Physics helpp
Newtons 2nd law The force of earths gravity is about 10 N downward. Whats the acceleration of a 15kg backpack if lifted with a 15N force??
Tuesday, May 14, 2013 at 10:49am

science physics
1.) What is the Magnitude of the electrostatic force on a +5 C charge 1.75 m to the left of a -2.5 C charge? (show your work) 2.) In What direction does the force on the +5 C charge act? 3.)Calculate the magnitude of the electric field of the -2.5 C charge at the location of ...
Tuesday, May 14, 2013 at 10:42am

physics
What is the magnitude of the electrostatic force on a +5 C harge 1.75 m to the left of a -2.5 C Charge? (show your work)
Tuesday, May 14, 2013 at 10:38am

Physics
Newtons second law What net force acting on a 14kg wagon produces an acceleration of 1.5 m/s^2?
Tuesday, May 14, 2013 at 9:52am

Physics
SD TRUSS PROBLEM WITH THE METHOD OF JOINTS The truss structure ABCD is loaded with a concentrated force P = 2 kN applied at a 45° angle at joint D as indicated in the figure. All bars in the truss have equal cross sectional area and are made of the same homogeneous linear ...
Tuesday, May 14, 2013 at 7:38am

Physics to Elena
Ex=0 ; Ez=0 Ey = 10 sin(3.14x - 6.08e8 t) what is the time-averaged Poynting vector (magnitude and direction) for the position x=y=z=−3 ?
Tuesday, May 14, 2013 at 4:59am

Physics to Elena
An optical fiber is a flexible, transparent fiber devised to transmit light between the two ends of the fiber. Complete transmission of light is achieved through total internal reflection. This problem aims to calculate the minimum index of refraction n of the optical fiber ...
Tuesday, May 14, 2013 at 4:38am

Physics to Elena
At the upper surface of the earth's atmosphere, the time-averaged magnitude of the Poynting vector is referred to as the solar constant and is given by </S/>=1.35×103W⋅mͨ2;2 . (a) If you assume that the sun's electromagnetic radiation is a ...
Tuesday, May 14, 2013 at 4:38am

physics
A steel rod of length 1m is heated from 25°c to 75°c keeping its length constant.The longitudinal strain developed in the rod is:(steel:12 X 10^-6/°c) "6X10^-4" ; "-6X10^-4" ; "0" please help me as soon as possible by explain this.
Tuesday, May 14, 2013 at 3:07am

Physics
- The Mariana trench is located in the Pacific Ocean at a depth of about 11000 m below the surface of the water. The density of seawater is 1025 kg/m3. (a) If an underwater vehicle were to explore such a depth, what forces would the water exert on the vehicle’s ...
Monday, May 13, 2013 at 11:07pm

physics
Name of physics book for 11 and 12.to catch engineering exam and other competetive exam
Monday, May 13, 2013 at 2:55pm

physics
A resistor of resistance R is connected to a power supply of constant EMF E=12 V and internal resistance r=3 Ω . The energy dissipated in the resistor R is used to heat water. What resistance R in Ohms gives the maximum power dissipated in the resistor?
Monday, May 13, 2013 at 1:30pm

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