Isaac newton’s investigations of gravity explained which of the following?

a. earth is not the center of the universe.

b. jupiter has more moons than earth.

c. gravity acts on all objects in the universe.

d. the sun is more massive than earth.

Aplayground slide is 8.80 ft long and makes an angle of 25.0° with the horizontal. a 63.0-kg child, initially at the top, slides all the way down to the bottom of the slide. (a) choosing the bottom of the slide as the reference configuration, what is the system's potential energy when the child is at the top and at the bottom of the slide? what is the change in potential energy as the child slides from the top to the bottom of the slide? (include the sign of the value in your answer.)