Posted by Steve on .
A 5.7 kg concrete block rests on a level table. A 4.0 kg mass is attached to the block by a string passing over a light, frictionless pulley. If the acceleration of the block is measured to be 1.0 m/s2, what is the coefficient of friction between the block and the table?

Physics 
drwls,
The net force pulling the 5.7 kg block is
Fnet = M1*a = 5.7*1.0 = 5.7 N
That equals the string tension M2*g minus the friction force M1*g*U
5.7 = M2*g  M1*g*U
M1 = 5.7 kg
M2 = 4.0 kg
Uk = kinetic friction coefficient
g = 9.8 m/s^2
Solve for U