Zorch, an archenemy of superman, decides to slow earth’s rotation to once per 28.0 h by exerting an opposing force at and parallel to the equator. superman is not immediately concerned, because he knows zorch can only exert a force of 4.00×107n (a little greater than a saturn v rocket’s thrust). how long must zorch push with this force to accomplish his goal?

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.