Question

A cord is used to lower vertically a block of mass M by a distance d with constant downward acceleration g/4. Work done by the cord on the block is ?

Answer 1

Answer:

-3Mgd/4

Explanation:

Let T be the tension in the string.

Mg - T =Mg/4

T = Mg - Mg/4

T = 3 Mg/4

Therefore, W = -T × D

= -3Mg/4 ×d

= -3Mgd/4....

Answer 2

Answer:

-3Mgd/4

Explanation:

Let T be the tension in the string.

Mg - T =Mg/4

T = Mg - Mg/4

T = 3 Mg/4

Therefore, W = -T × D

= -3Mg/4 ×d

= -3Mgd/4