A particle is projected up the incline such that its component of velocity along the incline is `10 ms^(-1)`. Time of flight is 4 sec and maximum heig

Monjur Alahi

A particle is projected up the incline such that its component of velocity along the incline is `10 ms^(-1)`. Time of flight is 4 sec and maximum height above the incline is `5m`. Then velocity of projection will be :
A. `10 ms^(-1)`
B. `10 sqrt2 ms^(-1)`
C. `5 sqrt5 ms^(-1)`
D. None


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Salim Ahmed Kawsar

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Correct Answer - C
`T = (2u_(y))/(a_(y)) = 4`
`H = (u_(y)^(2))/(2a_(y)) = 5`
`(T)/(H) = (4)/(u_(y)) = (4)/(5)`
`u_(y) = 5`
`u_(x) = 10` (given)
`u = sqrt(10^(2) + 5^(2)) = sqrt125 = 5 sqrt5`

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