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A ball is gently dropped from a height of 20m. If the velocity increases uniformly at the rate of 10 meter per second square, with what velocity will it strike the ground? After what time will it strike the ground? |
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Answer» Let us assume, the final VELOCITY with which the ball will strike the GROUND be ‘v’ and the time it takes to strike the ground be ‘t’.Given parametersInitial Velocity of the ball (u) = 0Distance or height of FALL (s) = 20 mDownward ACCELERATION (a) = 10 m s-2As we know★ 2as = v2 – u2 ⟼ v2 = 2as + u2 ⟼ v2 = (2 x 10 x 20 ) + 0 ⟼ v2 = 400Final velocity of ball (v) = 20 ms-1★ t = (v – u)/aTime taken by the ball to strike (t) = (20 – 0)/10 ⟼ t = 20/10 ⟼ t = 2 secondsThe final velocity with which the ball will strike the ground is (v) = 20 ms-1The time it takes to strike the ground (t) = 2 seconds |
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