Sample Exam III
  Visit the site on Sunday for answers and perhaps solutions(?).
  


1) You want to build a ski lift for a small hill resort. The hill is sloped at 200to the horizontal
     and  a 100 kg skier is to be pulled along the sloping side of the hill through a distance of 
     50m. The skierıs speed is 0 m/s at the bottom and 6.0 m/s at the top. If µk  is 0.05, what is the
     tension needed in the cable pulling the skier? ( Answer: 417 N.)
Solution:

2) A bullet of 10 g mass moving horizontally with a velocity of 505 m/s hits a wooden block 

    of 10 kg mass sitting on a horizontal table and gets embedded inside the block. After the 

    collision the block moves through a distance of 10 m on the table before coming to rest. 

    Compute the µk of the surface and the block






.:
Solution  The answer is 0.001 and not 0.01 and all except the last number  are correct.


3) A 12 kg bomb is projected upwards with an initial Vy = 9.8 m/s. At the highest point it breaks 

     up into two pieces with mass ratio of 1:2. The larger fragment falls downwards with a 

     velocity of 9.8 m/s. Find total vertical distance traveled by the smaller piece form the 

     launching point of the bomb.( Answer: 24.5 m.)
Solution  for 3 and 4.
            

4) A lumberjack of mass of 100 kg is at rest at one end of 10 ft log of mass 200 kg which is also
     
    at rest relative to the shore. Now he runs to the other end of the log reaching velocity of 6 m/s 	
    
    relative to the shore at the very end of the log in 10 seconds and then jumps upon an identical 

    log  at rest with respect to the shore. Assume that logs move without friction on water. What is    

    the velocity of each of the logs with respect to the shore after he lands on the second one?	
    (Answer: vel of the first  log -3 m/s and the second one 2 m/s.)
Solution for 3 and 4.
	
5) An elevator car of mass 800 kg with zero initial downward velocity falls from a 

     height of 5 m, hits a buffer spring and compresses it by  0.7 m before coming to rest. What 
	
     is the force constant of the spring? Was done in class.
     						

6) Chap 6 Sec 5. Circular Motion - Centripetal Acceleration.



7) Home work assignments and Class examples and Activity computations.

Go to additional Problems( Should be available after 4:00 P.M. on Friday)