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Chapter 8: Momentum, Impulse, and Collisions
1.) When a large, heavy truck collides with a passenger car, the occupants of the car are more likely to be hurt than the driver. Why?
2.) A net force of 4 N acts on an object initially at rest for 0.25 seconds and gives it a final speed of 5 m/s. How could a net force of 2 N produce the same final speed?
3.) A baseball has mass of 0.145 kg. If the velocity of a pitched ball has a magnitude of 45.0 m/s and the batted ball’s velocity is 55.0 m/s in the opposite direction, find the magnitude of the change in momentum of the ball and of the impulse applied to it by the bat. If the ball remains in contact with the bat for 2.00 milli-seconds, find the magnitude of the average force applied by the bat.
4.) A very heavy SUV collides head-on with a very light compact car. Which of these statements about the collision are correct?
a. The amount of kinetic energy lost by the SUV is equal to the amount of kinetic energy gained by the compact.
b. The amount of momentum lost by the SUV is equal to the amount of momentum gained by the compact.
c. The compact feels a considerably greater force during the collision than the SUV does.
d. Both cars lose the same amount of kinetic energy.
Longer Problem:
A ballistic pendulum is a system for measuring the speed of a bullet. The bullet, with mass mB = 5.00 g, is fired into a block of wood with mass mW = 2.00 kg, suspended like a pendulum, and makes a completely inelastic collision with it. After the impact of the bullet, the block swings up to a maximum height y = 3.00 cm. Given these values, what is the initial speed v1 of the bullet?