You pull a 70-kg crate at an angle of 30° above the horizontal. If you pull with a force of 600N and the coefficient of kinetic friction is .4, how far will it move in 3 seconds?

Answer 1

First, you need to draw a free body diagram. There will be an x component (governing horizontal acceleration) and a y component (used to determine the friction force)

in x: F_x - F_f = ma_x (F_x = Fcosθ and F_f = μF_N)

in y: F_N = F_W - F_y = mg - Fsinθ

Therefore, a_x = 1/m (Fcosθ - μ(mg - Fsinθ))

Because it is starting from rest, you know that d = 1/2 a_xt²

All units are in MKS, so you can solve by plugging into the equations.