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A ball is gently dropped from a height o...

A ball is gently dropped from a height of 20m. If its velocity Increases uniformly at the rate of `10 ms^(-2)` . With what velocity will it strike the ground? After what time will it strike the ground?

Text Solution

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Given : height =20 m
acceleration =`10 ms^(-2)`
Formula : For free falling body, (i) v = gt (ii) s=1/2 `"gt"^2`
time taken to strike the ground =`s=1//2 "gt"^2`
`20 m=1//2xx 10ms^(-2) xxt^2`
`r^2="40 m"/(10 ms^(-2))=4s^2`
`therefore` t=2s
(ii)Velocity of the ball when it strikes ground v=gt
`v=10 ms^(-2) xx2s`
`v=20ms^(-1)`
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Knowledge Check

  • A circket ball falls from a height of 40 m. What is the velocity with which the ball hits the ground ?

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    B
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    C
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