Why is a well-insulated building comfortable in both cold and hot weather? the insulation keeps the cold in during the summer and the cold out in the winter. the insulation becomes a good conductor in the cold weather. the insulation becomes a good conductor in the hot weather. the insulation keeps the heat in during the winter and the heat out in the summer.

A100-watt light bulb illuminates a solar cell. the electricity from the solar cell operates a water pump that delivers 1 watt of power. what is the efficiency of the system?

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration

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.