Chapter 12.1, Problem 12.22P

To unload a bound stack of plywood from a truck; the driver first tilts the bed of the truck and then accelerates from rest Knowing that the coefficients of friction between the bottom sheet of plywood and the bed are us ${\mu }_s=0.40$ and ${\mu }_k=0.30$ determine (a) the smallest acceleration of the truck which will cause the stack of plywood to slide, (b) the acceleration of the truck which causes corner A of the stack to reach the end of the bed in 0.9 s.