TUTORIAL SESSION 9 - Collisions

1.  What is meant by elastic collision? What is an inelastic collision? What is a completely inelastic collision?

2.  Consider the following collision between two blocks.

a)  What is the velocity v?

b)  Is the collision elastic?

3.  A cart of mass 340g moving on a frictionless track at an initial speed of 1.2m.s-1 strikes a second cart of unknown mass. The collision is elastic. If the first cart continues after the collision with a speed of 0.66m.s-1 in the original direction find the mass and speed of the second cart.

4.  A 60.0kg sled is coasting on ice at 9.0m.s-1 when a 12kg package is dropped onto it from above. What is the new speed of the sled?

5.  Two balls undergo an elastic head-on collision. The mass of ball A is 2.0kg and has an initial speed of 8.0m.s-1, the mass of ball B is 4.0kg and has an initial speed of 5.0m.s-1.

a)  Find the total momentum of the balls.

b)  Find the total kinetic energy of the balls.

c)  Find the velocities of the balls after the collision.

6.  A 25 000kg truck moving at 80km.h-1 has a head-on collision with a car of mass 950kg travelling at 70km.h-1.

a)  If the collision is inelastic find the final velocity of the truck-car mass.

b)  How much kinetic energy is lost in the collision?

7.  A bullet of mass 10g strikes a ballistic pendulum of mass 2.0kg. The bullet remains in the pendulum and the pendulum rises a vertical distance of 12cm. What is the bullet’s initial speed?

8.  What is impulse?

9.  A 55kg athlete is running at a speed of 4.2m.s-1. What impulse will stop her?

10.  A cue stick strikes a pool ball, exerting an average force of 50N over a time of 10ms. If the ball has a mass of 0.2kg. What speed does it have after impact?

11.  A golfer hits a golf ball giving it a speed of 50m.s-1. If the mass of the ball is 46g and the club and ball are in contact for 1.7ms what is the average force exerted by the club on the ball?

12.  The force on a 10kg object increases uniformly from 0 to 50N in 4s. What is the object’s final speed if it started from rest?

13.  Two marbles approach each other with the same speed and collide head-on elastically. After the collision, one of the marbles (with a mass of 300g) remains at rest. What is the mass of the other marble?

Student Learning

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