Acrate is carried in a pickup truck traveling horizontally at 15.0 m/s. the truck applies the brakes for a distance of 28.7 m while stopping with uniform acceleration. what is the coefficient of static friction between the crate and the truck bed if the crate does not slide?

Two cannon balls weighing 18 kg and 24 kg are chained together and fired horizontally with a velocity of 165 m/s from the top of a 21-m wall. the chain breaks during the flight of the cannonballs and the 18-kg cannonball strikes the ground at t = 1.5 s, at a distance of 240 m from the foot of the wall, and 7 m to the right of the line of fire. determine the position of the other cannonball at that instant. neglect the resistance of the air.