Question

Torque question:

An essentially weightless shovel is 120 cm long. Someone holds it horizontally, supporting it with his left hand at the shovel's center of gravity and his right hand 80.0 cm to the right of the c.g. The shovel contains a 20 N rock whose cg is 8 cm to the right of the edge of the shovel. How much force does the person exert down on the handle?

Answer is supposed to be 8 N but I'm having difficulty drawing out the diagram. Also, where would the center of gravity be located on a weightless object. Determining the distance/lever arm from the axis of rotation and the direction that the forces act are what I'm stuck on - isn't the force that the right hand exerts upward and not downward in order to balance the weight of the rock that the shovel holds (causing a clockwise torque?)

Answer 1