A ball after having fallen from rest under the influence of gravity for 6 s crashes through a horizontal glass plate, thereby losing two-third of its velocity. It then reaches the ground in 2 s, find the height of the plate above the ground.

Explanation

To solve the problem step by step, we can break it down as follows:

### Step 1: Calculate the velocity of the ball just before it hits the glass plate
The ball falls from rest under the influence of gravity for 6 seconds. We can use the formula for final velocity:

\[ v = u + at \]
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