The ball is dropped from a bridge ` 122.5 m` above a rivet, After the ball has been falling for 2 s, a second ball is thrown straight down after it. What must its initial velocity be so that bothe hit the warer at the same time ?

Explanation

To solve the problem step by step, we will analyze the motion of both balls and determine the initial velocity required for the second ball to hit the water at the same time as the first ball.

### Step 1: Understand the motion of the first ball
The first ball is dropped from a height of 122.5 m. Since it is dropped, its initial velocity (u1) is 0 m/s. The time taken for the first ball to reach the water can be calculated using the equation of motion:

\[ s = ut + \frac{1}{2}gt^2 \]
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