Can u plzz help meee

How have the competing explanations' experiments on atoms affected the development of the atomic model?

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.

Relative to the ground below, how many joules of potential energy does a 1000-kg boulder have at the top of a 5-m ledge?