Physics Lab First Semester Final – Part II

Read each question carefully, draw a diagram where appropriate and show your work for partial credit.  Remember to put your answers in  significant figures. Be careful to put your calculator in radians or degrees depending on the problem.  Good Luck!

1.         In a basketball game a 70.0 kg player is running a fast break and takes off for a dunk.

What is the player’s weight?

How much work does the player do if he applies a force of 1250 N over a distance of 0.500 m while jumping?

If all of that work is converted to kinetic energy, at what velocity does he leave the ground?

If he takes off at a 60 degree angle,  how far does he jump horizontally, assuming that he lands with his legs in the same position that he took off in?

What is the maximum height the player reaches?

2.         A police officer is sitting by the side of the road when a speeder passes him at 142 km/hr.  What is this speed in m/s?

After two seconds he takes off after him with a constant acceleration of 6.4 m/s.  How long will it take him to reach the same speed of the speeder?

How many meters behind the speeder is the police officer at this point?

Draw a sketch of a velocity-time graph showing the velocity of the police officer and the speeder.

3.         A coin (m = 0.00500kg)  is placed 0.11 m from the axis of a rotating turntable of variable speed.  The coin will remain on the turntable until a rate of 39 rpm (revolutions per minute) is reached, at which point the coin slides off.

What is the angular velocity of the turntable in radians per second at this speed?

If the turntable’s radius is a disk of mass 0.80 kg and radius 0.28 m, what is it’s moment of inertia?    What is its kinetic energy?  Its angular momentum?

What is the centripetal force on the coin provided by the friction?

What is the coefficient of friction?

4.         A 1.25 kg block of wood is hung from a thin cord.   A bullet is then fired from a gun at the hanging block.

The gun exerts a force of 1.35 x 104 N on the bullet.  If this force acts for 0.001 seconds, what will be the velocity of the 0.05 kg when it leaves the gun?

If the bullet collides and sticks in the block, what will be the speed of the bullet and block following the collision?

What is the KE of the block and bullet assuming half the KE is conserved?

How high above its original point will the cord swing if all the KE is turned into PE?

5.         Look at the diagram below.  A block of mass 3 kg hangs from a pulley.  Another block with a mass of 2 kg sits on the incline plane which has an angle of 37 degrees.

The force of friction has a magnitude of 4.5 N.

Label the forces present in the problem on the diagram.

What is the net force on the system?

What is the acceleration of the system?

How far will the 3kg block have fallen in 1.3 seconds if it starts from rest?

6.         The sign drawn below is held by two cables.  The tension in cable one is 680 N.  What is the tension in cable two?  The two angles are 40 and 60 degrees respectively.

If the sign is 9 m above the ground and the cables are cut, how long would it take for the sign to fall to the ground?

How fast would the sign be going just before it hit the ground?