A 60lb block rests on a smooth plane incline at 20 with horizontal The block is pulled up the plane with a force of 30lb parallel to the plane What is the accelaration?

Answer 1

The component of the force parallel to the incline is 30 lb * sin(20°) = 10.27 lb. The net force on the block up the incline is 10.27 lb - frictional force. The frictional force is equal to the block's weight component parallel to the incline, which is 60 lb * sin(20°) = 20.53 lb. So, the net force causing acceleration is 10.27 lb - 20.53 lb = -10.26 lb. Using F = ma, the acceleration a = (-10.26 lb) / (60 lb) = -0.17 ft/s^2 down the incline.