Instructions:Select all the correct answers.
 A free-falling golf ball strikes the ground and exerts a force on it. Which sentences are true about this situation?
 1. A golf ball striking the ground is a collision.
 2. The ground exerts an equal force on the golf ball. 
 3. The ground doesn’t exert a force on the golf ball.
 4. The force is zero because the golf ball has little mass.