Two men support a uniform horizontal beam at its two ends, if one of them suddenly lets go, the force exerted by the beam on the other man will

Options

A. remain unaffected
B. increase
C. decrease
D. become unequal to the force exerted by him on the beam

Answer

C

Explanation

When both support, the force exerted by each =`(mg)/2`

when one leave
`tau="mg "{l/2}=Ialpha=(ml^(2))/3alpha`
`alpha=(3"g")/(2l)Rightarrowa_(CM)=(l/2)xx(3"g")/(2l)=(3"g")/4`
`"So mg"-N=m{(3"g")/4}RightarrowN=(m"g")/4`