Work Energy And Power Question 213

Question: A cord is used to lower vertically a block of mass M, a distance d at a constant downward acceleration of $ g/4 $ . The work done by the cord on the block is

Options:

A) $ Mg\frac{d}{4} $

B) $ 3Mg\frac{d}{4} $

C) $ -3Mg\frac{d}{4} $

D) $ Mgd $

Show Answer

Answer:

Correct Answer: C

Solution:

[c] As the cord is trying to hold the motion of the block, work done by the cord is negative.

$ W=-M( g-a )d $

$ =-M( g-\frac{g}{4} )d=\frac{-3Mgd}{4} $



NCERT Chapter Video Solution

Dual Pane