The e ~ k relationship for the bottom of the conduction band of a semiconductor is of the form e = ak2 where a = 5 x 10-37 jm"". determine the effective mass of the electrons in the conduction band for this semiconductor and express the answer as a fraction of the free electron mass.

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

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.

Four friends, a, b, c, and d are standing varying distances away from a speaker which is producing sound waves.