Answer to Question #69048 in Mechanics | Relativity for Blessie

Question

A uniform plank of length 8 metres and weight 100 N rests horizontally on two trestles A and B, which are placed 2 metres from each end of the plank. A man of weight 600 N placed his toolbox of weight 20 N, 1 metre from the left-hand end of the plank. He is 3 metres from trestle A (or 3 metres from the
right end of the plank).The man gradually walks to the right. How far to the right of B can we move before the plank just lifts itself from the trestle A.

Answer 1

Taking the moments about the right support
∑▒〖M=0〗
20(7)+3/4(100)(3)=600(x-1)+1/4(100)(1)
x=1.57 m.
Answer: 1.57 m.