Question

. If the lever arm of a screw is 18 inches long and the pitch of the threads is 0.125

inch, how much weight will the jack lift if 50 pounds of force is applied at the end

of the lever arm ignoring friction?

Answer 1

The weight is

$$W=F·\frac{2\pi R}{p}=50·\frac{2\pi 18}{0.125}=45.2·10^3\text{ lb}.$$