A ball is released from the top of a tower. The ratio of work done by force of gravity in 1st second, 2nd second and 3rd second of the motion of ball is

Options

A. `1:2:3`
B. `1:4:9`
C. `1:3:5`
D. `1:5:3`

Answer

C

Explanation

`S_(1) = u+g/2 (2xx1-1)= g//2 `
`S_(2) = u + g/2 (2xx2-1) = 3g//2 `
`S_(3) = u + g/2 (2xx3-1) = 5g//2 `
`S_(1):S_(2):S_(3) = 1:3:5 (u = 0 )`
the for work done , force acting is mg each true
`W_(1) = F.S_(1)=mgS_(1)`
`W_(2) = F.S_(2)=mgS_(2)`
`W_(3) = F.S_(3)=mgS_(3)`
`W_(1)=F.S_(1)=mgS_(1)`
`W_(1):W_(2):W_(3) = 1:3:5 `