1. The diagrams below are graphs of Force in kiloNewtons versus time in milliseconds for the motion of a 5-kg block moving to the right at 4.0 m/s.
   (a) What is the magnitude and direction of the impulse acting on the block in each case?
   (b) What is the magnitude and direction of the average force acting on the block in each case?
   (c) What is the magnitude and direction of the final velocity of the block in each case?
   
2. The diagrams below are the velocity versus time graphs for the collision of motion of a 4-kg block with a wall. The collision lasts for 20 milliseconds in each case.
   (a) What is the magnitude and direction of the impulse acting on the block in each case?
   (b) What is the magnitude and direction of the average force acting on the block in each case?
   
3. You've been rowdy and obnoxious in a bar and are now in the process of being thrown out by the scruff of the neck by the bouncer. The bouncer has hold of you for 5.0 s and you are take from a seated position to a final speed of 2.75 m/s. If your mass is 70.0 kg, what was your final momentum? What impulse and average force did the bouncer exert on your person? Assume all motion is in a straight line.

4. A ball of mass 0.500 kg with speed 15.0 m/s collides with a wall and bounces back with a speed of 10.5 m/s. If the motion is in a straight line, calculate the initial and final momenta and impulse. If the ball exerted an average force of 1000 N on the wall, how long did the collision last?

5. A ball of mass 0.25 kg glances of a wall as shown in the diagram. The ball approaches at 15 m/s at θ = 30° and leaves at 12 m/s at φ = 20°. The collision lasts for 15 milliseconds.
   (a) What are the components of the impulse experienced by the ball?
   (b) What are the components of the average force acting on the ball?
   
6. Explain why a person wearing a seatbelt in a car accident is less likely to be seriously hurt than the person who isn't wearing a seatbelt.

7. A lion of mass 120 kg leaps at a hunter with a horizontal velocity of 12m/s. The hunter has an automatic rifle firing bullets of mass 15 g with a muzzle speed of 630m/s and he attempts to stop the lion in midair. How many bullets would the hunter have to fire into the lion to stop its horizontal motion? Assume the bullets stick inside the lion.

8. On a frictionless surface, a 6.0-kg rock approaches from the left at 3.5 m/s. It collides elastically with a 9.0-kg rock which is approaching from the right at 1.7 m/s. Find the final velocities of the rocks.

9. If the collision in question #5 had a coefficient of restitution is 0.60, what would have been the final velocity of the rocks? How much kinetic energy would have been lost in the collision?

10. If the collision in question #5 had been perfectly inelastic, what would have been the final velocity of the rocks? How much kinetic energy would have been lost in the collision?

11. A 50.0-kg skater is traveling due east at 3.00 m/s. A 70.0-kg skater is moving due south at 7.00 m/s. They collide and hold on to one another after the collision. Determine the magnitude and direction of their velocity after the collision. Ignore the effects of friction.

12. Football player A tackles and holds onto player B in the diagram below.
    
    1. Assuming friction is negligible, what is the velocity of the players just after the collision?
    2. If the collision lasts for 0.30 seconds, what average force (magnitude and direction) does player A exert on player B?
    

13. A curling rock is traveling down the ice when it mysteriously explodes into three parts. After the explosion, one piece having 27.0% of the total mass moves at a speed of V_1f = 14.2 m/s at an angle of 42.0° to the positive y axis. A second with 52.0% of the total mass move at a speed of V_2f = 18.9 m/s at an angle of 17.8° to the positive x axis. The third piece moves with speed V_3f = 35.9 m/s at 39.0° to the negative y axis. What was the speed of the stone before the explosion?
    

14. Two opposing hockey players are racing up the ice for the puck when they collide at point A as shown in the diagram below. The first hockey player has mass 90 kg and a speed of 2.7 m/s while the other has mass 82 kg and speed 3.1 m/s. The angle in the diagram is θ = 32° . After the collision, the players remain locked together (at least until the referee forces them apart). What is the magnitude and direction of the players' velocity just after they collide?
    
15. The distance between the oxygen molecule and each of the hydrogen atoms in a water (H₂O) molecule is 0.0958 nm; the angle between the two oxygen-hydrogen bonds is 105°. Treating the atoms as particles, find the centre of mass.
    

16. Where is the centre of mass of a uniform cubic box of side length L which has no lid?
    

17. Two uniform squares of sheet metal of dimension L × L are joined at a right angle along one edge. One of the squares has twice the mass of the other. Find the centre of mass.
    

18. A cube of iron has dimension L × L × L. A hole of radius ¼L has been drilled all the way through the cube, so that one side of the hole is tangent to one face along its entire length. Where is the centre of mass of the drilled cube?
    

19. An 80-kg logger is standing on one end of a 10-m long, 300-kg, tree trunk in the middle of the Fraser River. The logger walks upriver along the trunk to the other end of the log. As a result the log moves some distance L down river. What is the displacement L?
    

20. A shell is fired at 25 m/s at 25 above the horizontal. At the top of its parabolic flight, it breaks into two pieces. One piece, having two-thirds of the total mass of the shell lands 60 m from where the shell was fired. Where did the other piece land?

Questions? mike.coombes@kwantlen.ca