What is the standard unit of measurement of Force?
a) Newton
b) Joule
c) Meter
d) Newton-meter

Explanation

Let the minimum force exerted by the man is T
From the free body diagram, `
`R+T=Mg`
`rarr R=Mg-T`.i
Again R-R-mg-0`
`R_1=R+mg`..ii
`and T-muR_1=0`
From equatioon ii, `T-mu(r+mg)=0`
`rarr T-muR-mu mg=0`
`rarr T-mu(Mg-T)-mu mg =0`
`T-mu Mg+mut-mu mg =0`


`T(1+mu)=muMg+mumg`
`rarr T=(mu(M+m)g)/(1+mu)`
Maximum force exerted by man is `(mu(M+m)g)/(1+mu)`