A 3.5 kg mass sits at rest on a rough surface. The surface has the following coefficients of friction: µs = 0.53 and µk = 0.21. Determine the required force to start the object moving?
The µs "static" friction coefficientr is what determines whether it moves or not.
To make it move, you need a horizontal force of at least
F = M*g*µs = 18.2 N