A body of mass 1 kg is thrown upwards wi...

A body of mass `1 kg` is thrown upwards with a velocity `20 ms^(-1)`. It momentarily comes to rest after attaining a height of `18 m`. How much energy is lost due to air friction? `(g = 10 ms^(-2))`

20 J

30 J

40 J

10 J

Text Solution

Verified by Experts

The correct Answer is:

`K_1+U_1=K_2+U_2+W_f`
`W_f`: work done against friction
`(1)/(2)(1)(20)^2+0=0+(1)(10)(18)+W`
`200=180+W_f`
`W_f=20J`
Energy lost due to friction `=20J`

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