Question

A worker stands on a support and with the help of a block will lift the load evenly, the weight of which is 480 H (fig. 216). calculate the pressure produced by the support worker, if his weight is 720 N, and the foot area is 320 cm² (Friction and block weight can be neglected.)

Answer 1

Explanation:

Draw free body diagrams for the worker and the load.

The worker has three forces on him: normal force pushing up, weight pulling down, and tension pulling down.

The load has three forces on it: weight pulling down and two tension forces pulling up.

Sum of the forces on the load:

∑F = ma

2T - 480 N = 0

T = 240 N

Sum of the forces on the worker:

∑F = ma

N - 720 N - 240 N = 0

N = 960 N

So the pressure produced by the worker is:

P = F / A

P = 960 N / 320 cm²

P = 3 N/cm²

P = 30,000 Pa