A106 kg clock initially at rest on a horizontal floor requires a 670 n horizontal force to set it in motion. after the clock is in motion, a horizontal force of 557 n keeps it moving with a constant velocity.

a) what is the μs between the clock and the floor? .70
b) what is the μk between the clock and the floor?

a)

b)

Explanation:

Static friction is when the body is at rest or is about to move while kinetic friction is when the body is already in motion. According to Newton's second law:

a)  In this case, the static friction must be equal to the horizontal force to set the clock in motion:

b) In this case, the kinetic friction is equal to the horizontal force that keep the clock moving with constant velocity: