One morning, Lou was in a particularly deep and peaceful slumber. Unfortunately, he had spent the night in the back of a dump truck, and Barry, the driver, was keen to go off to work and start dumping things. Rather than risk a ruckus with Lou, Barry simply raised the back of the truck, and when it reached an angle of 30°, Lou slid down the 4-m incline in 2 s, plopped onto a pile of sand, rolled over, and continued to sleep. Calculate the coefficients of static and kinetic friction between Lou and the truck.