The stoplights on a street are designed to keep traffic moving at 26 mi/h. the average length of a street block between traffic lights is about 80 m. what must be the time delay between green lights on successive blocks to keep the traffic moving continuously? there are 1.609 × 103 m in a mile. answer in units of s

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.