Question
A horizontal plank 4.00 meter long and having mass 20.0 kg rests on two pivots, one at the left end and the second 1.00 m from the right end. Find the magnitude of the force exerted on the plank by the second pivot. bowling ball is held in a person's hand with the forearm horizontal, as shown in the figure. The biceps muscle is attached 0.0300 m from the joint, and the ball is 0.350 m from the joint. Find the upward F exerted by the biceps on the forearm (the ulna) and the downward force R exerted by the humerus on the forearm, acting at the joint. Neglect the weight of the forearm and slight deviation from the vertical of the biceps. Calculate the net torque (magnitude and direction) on the beam about (a) an axis through 0 perpendicular to the page and (b) an axis through C perpendicular to the page.
Explanation / Answer
1)d
2)d
3)a)29.62N-m
b)35.586N-m