# PHY 108 questions

Homework problems: Chapters 7 and 8

- An average force of 300 N acts on a golf ball for a time interval of 0.04 s. What’s the impulse acting on the ball?
- What’s the momentum of a 1200 kg car traveling with a speed of 25 m/s?
- A force of 45 N acts on a ball for 0.2 s. If the ball has a mass of 0.3 kg and is initially at rest:

a) What’s the impulse on the ball?

b) What’s the final momentum of the ball?

c) What’s the final velocity of the ball? - An ice skater with a mass of 80 kg pushes off against a second skater with a mass of 32 kg. Both skaters are initially at rest.

a) What’s the total momentum of the system after they pushed off?

b) If the larger skater moves off with a speed of 3 m/s, what’s the speed of the smaller skater? - A basketball with mass of 0.8 kg is moving to the right with velocity 6 m/s and hits a volleyball with mass of 0.6 kg that stays at rest. If the volleyball moves to the right with velocity 4 m/s after collision, what’s the final velocity of the basketball?
- A force F
_{1}= 20 N is applied to open a door at a distance 50 cm from the spindle. Another force F_{2}is trying to stop opening the door at a distance of 30 cm from the spindle. Find the force F_{1}to balance the door.

What are the differences between elastic and inelastic collisions?