Classical Mechanics Answers

In a ball game a 70 kg player is running at 10 m/s when he is hit by the other player he bounces off in the opposite direction at 2 m/s. What is the players change in momentum?

A Stationary lift raft with mass of 160 kg is carrying two survivors with masses of 55 kg and 72 kg, they dive off raft at the same instant the 55 kg person due east at 4.4 m/s and the 72 kg person due north at 4.2 m/s. At what speed and in what direction does the raft start to move?

A 1200 kg car traveling at 15 m/s due east collides with a 720 kg car traveling at 21 m/s due north. As a result of the collision the two cars lock together what is the velocity immediately after the collision?

75 kg ball player moving at a velocity of 7.8m/s hits a player moving in the opposite direction who has a mass of 90 kg. If they collide and stop to have a speed of zero how fast is the other player moving originally?

A particle P carries a charge e and moves under the influence of static magnetic field B(r) which exerts the force F × ev × B

on P, where v is the velocity of P . Show that P travels with constant speed.

A box, of mass 8 kg, is on a rough horizontal surface.

A string attached to the box is used to pull it along the surface.

The string is inclined at an angle of 40° above the horizontal.

The tension in the string is 50 newtons.

As the box moves a distance of x metres, its speed increases from 2ms1 to 5ms-1

The coefficient of friction between the box and the surface is 0.4

By using an energy method, find x.

An object is vertically projected at u velocity ..After t time another one is projected at the same velocity. Show the meeting time is (t/2 + u/g) after the first object projected .

Two bodies of masses M1 and M2 have equal energies.If P1 and P2 are their respective momentum,compute P1/P2.

A block slides down an inclined ramp such that it speeds up by 5 m/s/s. The ramp is not frictionless. The ramp makes an angle of 53° with respect to the horizontal. The mass of the block is 50 kg.

A. Draw a free-body diagram for the block.

B. Find the magnitude of the gravitational force exerted on the block. Show your work. (You may use g»10m/s²).

C. Draw an arrow on the diagram above to indicate the direction of the acceleration of the block. If the acceleration is zero, please state that explicitly.

D. Find the magnitude of the normal force exerted on the block by the ramp. Show your work and indicate which of Newton’s laws you used to find your answer.

E.  Use Newton's 2^nd Law to find the magnitude of the frictional force exerted on the block by the ramp. Show your work.  

F.  Find the coefficient of kinetic friction between the block and the ramp. Show your work.

The diagram at right shows an Atwood’s machine composed of a massless frictionless pulley, three identical blocks each of mass m₀, and two massless strings. Assume that the blocks are released from rest and that the strings do not stretch. 

      A. Describe the motion of block C.

      B. Is the magnitude of the force exerted by String #2 on block B greater than, equal to or less than the force exerted by String #2 on block C? Explain your reasoning.

      C. Is the tension in String #2 greater than, equal to, or less than the tension in String #1? Explain yo