A 21 kg box sits on a table. The coefficient of static friction s between table and box is 0.27, and the coefficient of kinetic

A 21 kg box sits on a table. The coefficient of static friction μs between table and box is 0.27, and the coefficient of kinetic friction μs is 0.22.

a) What is the magnitude of the force required to start the box moving?
F=______N

b) What is the magnitude of the force required to keep it moving at constant speed?
F=______N