A projectile is thorwn with a velocity of `50ms^(-1)` at an angle of `53^(@)` with the horizontal Detemrine the instants at which the projectile is at the same heightA. `t = 1s` and `t = 7s`B. `t = 3s` and `t = 5s`C. `t = 2s` and `t = 6s`D. all the above

A projectile is thorwn with a velocity of `50ms^(-1)` at an angle of `

1.	A projectile is thorwn with a velocity of `50ms^(-1)` at an angle of `53^(@)` with the horizontal Detemrine the instants at which the projectile is at the same heightA. `t = 1s` and `t = 7s`B. `t = 3s` and `t = 5s`C. `t = 2s` and `t = 6s`D. all the above
Answer» Correct Answer - D For same height `y = u_(y)t +(1)/(2) a_(y)t^(2) rArr y = u_(y)t - (1)/(2) "gt"^(2)` `"gt"^(2) - 2u_(y) +2h = 0 rArr t = (2u_(y)+-sqrt(4u_(y)^(2)-8gh))/(2g)` `t_(1) = `(u_(y)-sqrt(u_(y)^(2)-2gh))/(g), t_(2) =(u_(y)-sqrt(u_(y)^(2)-2gh))/(g)` `t_(1) +t_(2) =(2u_(y))/(g) = (2 xx 50 xx sin 53^(@))/(10) = 8sec`.

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A projectile is thorwn with a velocity of `50ms^(-1)` at an angle of `53^(@)` with the horizontal Detemrine the instants at which the projectile is at the same heightA. `t = 1s` and `t = 7s`B. `t = 3s` and `t = 5s`C. `t = 2s` and `t = 6s`D. all the above

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