A) The initial height of the light stone is greater than the initial height of the heavy stone.
D) Just as it reaches the ground, the light stone is traveling faster than the heavy stone.
E) The stones both have the same kinetic energy just as they reach the ground.
Explanation:
Potential energy is mass times gravity times height.
PE = mgh
Both stones initially have the same potential energy. Since the light stone has less mass, it must have a greater initial height. (A is true, B is false)
Energy is conserved, so if they have the same initial potential energy, they have the same final kinetic energy (E is true). Kinetic energy is half the mass times the square of velocity.
KE = ½ mv²
Since both stones have the same amount of kinetic energy when they land, and the light stone has less mass, the light stone must have greater speed (D is true, C is false).
