C15: Two marbles, one twice as heavy as the other, are dropped to the ground from the roof of a building. Just before hitting the ground, the heavier marble has

1. as much kinetic energy as the lighter one.

2. twice as much kinetic energy as the lighter one.

3. half as much kinetic energy as the lighter one.

4. four times as much kinetic energy as the lighter one.

5. impossible to determine