A body of mass 5 kg climb a height of 10 m by the force of 170 N . Its velocity at this height wil be `……….`

Options

A. 15 m/s
B. 37 m/s
C. `9.8` m/s
D. 22 m/s

Answer

D

Explanation

Work done by force W = Fh
`= 170 xx10`
` = 1700 J `
gravitational potential energy
U = mgh
` = 5 xx 10 xx10`
= 500 J
Now , kintic energy = `W - U `
` :. 1/2 mv^(2) = 1700 - 500`
` :. 1/2 mv^(2) = 1200 J `
` :. v = sqrt((2xx1200)/5) = sqrt((2400)/5)`
` :. v = sqrt(480)`
= `21.90`
` :. v = 22` m/s (approximate)