posted by Physics2hard4me .
A person pushes on a 56-kg refrigerator with a horizontal force of -260 N; the minus sign indicates that the force points in the -x direction. The coefficient of static friction is 0.58.
(a) If the refrigerator does not move, what are the magnitude and direction of the static frictional force that the floor exerts on the refrigerator?
(b) What is the magnitude of the largest pushing force that can be applied to the refrigerator before it just begins to move? Assume g = 9.8 m/s2.
a. M*g = 56 * 9.8 = 548.8 N. = Wt. of refrigerator = Normalforce(Fn).
Fs = u*Fn = 0.58 * 549 = 318.3 N. = Force of static friction.
b. Fap-Fs = M*a
Fap - 318.3 = M*0 = 0
Fap = 318.3 = Force applied.