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A massless rope is wrapped several times on a disc of mass M and radius R. The other end is tied to a mass m which at the beginning is at a height of h above ground as shown in the figure. When released the velocity of the mass as it touches the ground is A. `sqrt((4mgh)/(2m+M))`B. `sqrt(2gh)`C. `sqrt((4mgh)/(3M))`D. `sqrt((4mgh)/(M+m))` |
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Answer» Correct Answer - 1 `tau=Ialpha" " rArr TR=1/2 MR^(2)(a/R)` `rArr T=1/2 Ma` and `mg-T=ma` `mg =ma+1/2 Ma `or `a=(2mg)/(M+2m)` Velocity after a fall of height h is `v^(2)=2ah` `v=sqrt(2ah)=sqrt((4mgh)/(M+2m))` |
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