A woman attempts to push a box of books that has mass 37.5 kg up a ramp inclined at an angle of 24.5 degrees above the horizontal. Assume that the coefficients of friction between the ramp and the box are unknown, and symbolize them by s and k. The force F applied by the woman is HORIZONTAL, i.e. parallel to the ground, not to the ramp. Part A If s is greater than some critical value, the woman cannot start the box moving up the ramp no matter how hard she pushes. Calculate this critical value of s. Note: this critical value of s may be an unreasonably large value; i.e. something much larger than 1.0. B) Assume that s is 0.820 and that k is 0.270, and that the woman does decide to push horizontally. Once the box is moving, then what magnitude of horizontal force must the woman apply to keep the box moving up the ramp at constant speed