Answer to Question #57899 in Mechanics | Relativity for Tim
You hold a rock at a height 10 m above the ground and throw it downwards. Its total energy at the top is 200 J, but by the time it has reached the ground, friction and air resistance has removed 136 J. How much is its energy just before it hits the ground? What is the rock's speed just before it hits the ground? Assume its mass is 2.0 kg.