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A box of mass 50 k is pulled up on an in...

A box of mass 50 k is pulled up on an incline 12 m long and 2m high by a constant force of 100 N from rest. It acquires a velocity of 2m/s on reaching the top. Work done against friction is (Take `g=10m//s^(2)`)

A

50J

B

100J

C

150 J

D

200J

Text Solution

Verified by Experts

The correct Answer is:
B

The work done by the lifting mechanism (P.E+K.E.) of the elevator at B `=mgh+1/2mv^(2)`
`=1000 xx 10 xx 20 +1/2 xx 1000 xx 16 `
`=200 xx 106(3) +8 xx 10^(3)=208 xx 10^(3)J` and the work done against frictional force `=f xx h`
`=500 xx 20 =10 xx 10^(3)`
`therefore ` Total work done `=(208+10) xx 10^(3)=218 xx 10^(3)J`
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