Question

A block with mass m1 = 9.4 kg is on an incline with an angle θ = 26° with respect to the horizontal. For the first question there is no friction, but for the rest of this problem the coefficients of friction are: μk = 0.24 and μs = 0.264.

Answer 1

@pthom

For the first question you need to use neither of the coefficients. For the rest of the problem, that depends on what you are asked to find.

If the box is already in motion, then μk must be considered. If the box is at rest or someone is trying to put it in motion, then μs is what needs to be considered.