Arock dropped from a high platform is moving at 24 ms downward when it strikes the ground. ignore air resistance. how fast was the rock moving when it had fallen only one-fourth of the distance to the ground?

To practice problem-solving strategy 10.1 for energy conservation problems. a sled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slides a distance d1 down the slope and then covers the distance d2 along the horizontal terrain before stopping. find the coefficient of kinetic friction μk between the sled and the ground, assuming that it is constant throughout the trip.