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 F₁= 20 N is applied to open a door at a distance 50 cm from the spindle. Another force F₂is trying to stop opening the door at a distance of 30 cm from the spindle. Find the force F₁to balance the door.

What are the differences between elastic and inelastic collisions?