Answer to Question #145275 in Mechanics | Relativity for Syarif

Question

A simple manual winch consists of a drum of radius 4.0 cm to
which is attached a handle of radius 25 cm (Fig. 13.28). When
you turn the handle, the rope winds up on the drum and pulls
the load. Suppose that the load carried by the rope is 2500 N.
What force must you exert on the handle to hold this load?

Answer 1

Explanations & Calculations

• The figure should be something similar to this.
• Here some rotation is involved therefore, it's not enough to consider the forces, a consideration of the torques which those forces generate is rather needed.
• A sufficient torque should be generated as a counter to that already applied due to the load, in order to hold the load.
• Therefore,

$\qquad\qquad \begin{aligned} \small F\times 0.25m &= \small 2500N\times 0.04m\\ \small F&= \small \bold{400N} \end{aligned}$