Part A Which sentence best states the central idea of paragraphs 21-22 in "Energy Story"?

A. Materials that are insulators and conductors have a high
resistance to electricity.

B. It is more difficult for electricity to pass through insulators than conductors.

C. Insulators and conductors are able to generate a high amount of electricity

D. Electrons move through rubber easier than they move through
metal.

Asled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slidesa distance d1 down the slope and then covers the distance d2 alongthe horizontal terrain before stopping. find the coefficient ofkinetic friction μk between the sled and the ground, assumingthat it is constant throughout the trip. find the coefficient of kinetic frictionμk. express your answer in terms of someor all of the variables d1, d2, and θ.