posted by David S. on .
A box whose mass is 20 kg rests on a frictionless ramp with a 15 degree (upward) slope. A mover pulls up on a rope attached to the box to pull it up the incline. If the rope makes an angle of 40 degree with the horizontal, what force does the mover have to exert in order for the box to move up the ramp at a constant speed?
The compoment of the applied force F up the plane is F cos 25. With no friction, that must equal the weight component down the plane, which is M g sin 15 = 20*9.8* 0.2588
F = ?