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A person trying to lose weight by burnin...

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times. Assume that the potential energy lost each time he lowers the mass is dissipated. How much fat will he use up considering the work done only when the weight is lifted up? Fat supplies `3.8 x 10^(7) J` of energy per kg which is converted to mechanical energy with a `20%` efficiency rate. Take `g=9.8 ms^(–2)` :

A

`6.45 xx 10^(-3) kg`

B

`9.89 xx 10^(-3)kg`

C

`12.89 xx 10^(-3)kg`

D

`2.45 xx 10^(-3)kg`

Text Solution

Verified by Experts

The correct Answer is:
C
Let m mass of fat is used `m(3.8 xx 10^(7))(1)/(5)= 10(9.8) (1) (1000)`
`m= (9.8 xx 5)/(3.8 xx 10^(3)) = 12.89 xx 10^(-3) kg`
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