Question

Calculate the height from from which a body is released from rest if its velocity just before hitting the ground is30m\s

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Answer 1

height = 45 m

Step-by-step explanation:

Initial velocity = 0 m/s

Final velocity = 30 m/s

Acceleration due to gravity = +10m/s^2 ( because ball is going down )

Using the eqn of motion

`{v}^(2) - {u}^(2) = 2gh`

where v= final velocity ; u = initial velocity ; g = acceleration due to gravity ; h = height

So,

`{30}^(2) - {0}^(2) = 2 * 10 * h`

`= > 20h = 900`

`= > h = (900)/(20) = 45`