A mass M is lowered with the help of a string by a distance h at a distance acceleration `g//2`. The work done by the string will be

Options

A. `(Mgh)/(2)`
B. `-(Mgh)/(2)`
C. `(3Mgh)/(2)`
D. `-(Mgh)/(2)`

Answer

B

Explanation

Tension in the string :
`T = M(g - a) = M (g - g//2) = Mg//2`
`W = Force xx Displacement = - M (g//2) h`