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Form a lift moving upwards with a unifor...

Form a lift moving upwards with a uniform acceleration `a=2 m s^(-2), man throus a ball vertically upwards with a velcoity `v=`12 m s^(-1)` relative to the lift. The ball comes back to the man after a time `t`. Find the value of `t` in seconds.

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Taking upward direction as positive, let us workin the frome of lift. Acceleration of ball relative to lift `=(g+a)` downwards, so `a_(real) =- (g+a)`, initial velocity: `u_(rel) =v`, final velcity : `v_(rel) =v`, as the ball will reach the man with same speed w.r.t. lift Apply `v_(rel) =u_(rel)+ a_(rel)t rArr - v+ (g-a)t rArr t =2 s` .
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Knowledge Check

  • A ball thrown vertically upwards with an initial velocity of 1.4 m//s. The total displcement of the ball is

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    B
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    B
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    C
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    D
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