Please solve these questions in details and explaination. Thanks so much in advance.

Determine the smallest mass (in kg) of the man so that he can move the crate. The uniform crate has a mass of mc = 170 kg. The coefficient of static friction between the crate and the floor is us = 0.21. The coefficient of static friction between his shoes and the floor is us' = 0.4. Assume that the man exerts only horizontal force on the crate. Use a = 1.4 m, b = 2.5 m, c = 1.5 m, and g = 9.81 m/s2. mc b a