Consider an ideal gas being heated at constant volume, and let cv be the gas's molar heat capacity at constant volume. if the gas's infinitesimal change in temperature is dt, find the infinitesimal change in internal energy du of n moles of gas. express the infinitesimal change in internal energy in terms of given quantities.

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.