The door is at rest when the man M starts pushing it to the right with a constant horizont...

The door is at rest when the man M starts pushing it to the right with a constant horizontal force of 40 lb. If the weight of the door is 300 lb, its width and height are both ℓ = 10 ft, its center of mass G is at its geometric center, and the man pushes at a height h = 4 ft, determine the speed of the door after it has moved 10 ft and determine the reactions at the rollers A and B .

Figure P7.11