posted by Anonymous .
A 23 kg chair initially at rest on a horizontal
ﬂoor requires a 371 N horizontal force to set
it in motion. Once the chair is in motion, a
345 N horizontal force keeps it moving at a
The acceleration of gravity is 9.81 m/s
a) What is the coeﬃcient of static friction
between the chair and the ﬂoor?
The force required to make it move is
F = (mu_s)*W = (mu_s)*M*g
M is the chair's mass. Solve for mu_s
For question (a), you don't need the force needed to keep it oving.