WORK Simple qs

A bucket is tied to a string of mass M is lowered at a constant acceleration of g/4.If the mass of the bucket is M & is lowered by a distance d , the work done by the external agent on the string & bucket system will be ?

(A) Mgd/2 (B) - 3Mgd/2 (C) -3Mgd/4 (D) 3Mgd/2

6 Answers

3
iitimcomin ·

C

4
UTTARA ·

@iitimcoming : The ans is - 3Mgd/2

I got 3Mgd/2

I had a doubt regarding the ' - ' ve sign

1
fibonacci ·

Uttara can you please explain how the ans is -3Mgd/2. i got the - sign but how come magnitude is 3mgd/2

4
UTTARA ·

Mg - T = Mg/4

T= 3Mg/4

For the system T1 = 2Mg - Mg/2 = 3Mg/2

So, W = - 3Mgd/2

[tension is acting in upward direction.....hence angle between force and distance is 180

fxdcos180=-fd ]

1
Kaustab Sarkar ·

tension is acting in upward direction.....hence angle between force and distance is 180

fxdcos180=-fd

4
UTTARA ·

Thanks everyone

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