Question

Study the diagram and answer the questions that follow.

1. In the diagram, is the worker attempting to raise or lower the load?
2. Justify your answer to (a) with the necessary calculation.

Answer 1

(a) The worker is attempting to raise the load.

(b) Taking the distances shown in the diagram, the load is 2 m from the pivot and the counterweight is 4 m from it.

Weight of the load = 4000 kgf × 9.8 N/kgf = 39,200 N

Moment of the load = 39,200 × 2 = 78,400 N m

Moment of the counterweight = 20,000 × 4 = 80,000 N m

The counterweight produces the greater moment, so it turns the crane in the direction that raises the load.