Question

a ball is dropped from a bridge of 122.5m above a river.after the ball has been falling for 2sec.a second ball is thrown straigjt down after it.initial velocity of second ball so that both hits the water at same time is

Answer 1

Hey, refer to image attached.

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Answer 2

Answer:

26.133 m/s

Explanation:

Time taken by first ball to hit water can be found as

s= ut + ½ gt2

122.5 = ½ * 9.8 * t2

t2= 25

t =5

Now the next ball must cover this distance in 3 s to hit water at same time.

122.5 = 3 u + ½ * 9.8 * 32

122.5 = 3u + 44.1

3u = 78.4

u= 26.133 m/s