A man drops 10 kg rock from the top of a 5.0 metre ladder. What is its kinetic energy when it reaches the ground? What is its speed just before it reaches the ground?

1. 490J,7root2 m/s.         2. 290J, 7 m/s
3. 190J,7root2 m/s.         4. None

Given,
 Mass = 10 kg
Height = 5 m