A steel block is extends a spring 14cm when hung from it. When drawn across a surface using the same spring at a constant speed, the spring extends 3 cm. What is the coefficient of friction?

Help?

We get friction using the formula F = u * mg and the extension of the cylinder seems to imply Hooke’s law is relevant; F = k * l.

Question

A steel block is extends a spring 14cm when hung from it. When drawn across a surface using the same spring at a constant speed, the spring extends 3 cm. What is the coefficient of friction?

Help?

We get friction using the formula F = u * mg and the extension of the cylinder seems to imply Hooke’s law is relevant; F = k * l.

anonymous · Answer

hanging:
mg = kx = k*.14
k=mg/.14

dragging:
kx = mu*mg
k*.03 = mu*mg
(mg/.14)*.03 = mu*mg
.03/.14 = mu