In moving a 35kg desk from one side of a room to another, a man finds that a horizontal force of 275N is necessary to set the desk in motion, and a force of 195N is necessary to keep it in motion at a constant speed. What are the coefficients of both static friction and kinetic Friction between the desk and the floor?


Show all your calculations.

1 answer

M*g = 35 * 9.8 = 343 N. = Wt. of the desk = Normal force(Fn).

A. Fap-Fs = M*a.
275-Fs = 35*0
275-Fs = 0
Fs = 275 N. = Force of static friction.
us = Fs/Fn = 275/343 =[

B. Fap-Fk = M*a.
195-Fk = 35*0
Fk = 195 N. = Force of kinetic friction.

uk = Fk/Fn = 195/343