Answer : 3 30 m/s Explanation : Answer: C) 30 m/s Explanation: The interval between object pass the same point is 4 sec.That means in 2 sec, object reaches the top and in next 2 sec, it again reaches the same point.By the info given, we can find the velocity of that point by using : v=u (-gt)0= u - 10×2u = 20Then the velocity at 25m is 20m/sec.so the initial velocity is-v2 = u2 (-2gh)400 = u2 - 2x 10 x 25u2 = 900 =

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