A box is pushed up a frictionless ramp. The box has a mass of 5.6 kg and the pushing force acts in a direction parallel to the ramp.

Question

The ramp is at an angle of 15 degrees with the horizontal. If the acceleration of the box is 2 m/s² up the ramp, what is magnitude of the pushing force? (Answer in Newtons)

Answer 1

Basically, there are two "competing" forces that determine the acceleraion of the block.

1) F_(applied) in the upward direction. 2) The component of F_(gravity) along the surface of the path.

Then, we apply Newton's 2^nd Law:

∑F_net = ma

F_(applied) - mgsin15 = ma = m x 2 ==> F_(applied) = (5.6 x 9.8 x 0.65) + (5.6 x 2) = F_(applied)

F_(applied) = 35.67 + 11.2 = 46.87 ∼ 47N