- Time when it reaches the glass pane = 5 seconds.
- It loses ½ velocity after it strikes the glass pane.
- Initial velocity (u) = 0 .
- g = 10 m/s².
Velocity through it strikes the glass pane (v) = ?.
Applying first kinematics equation,
Substituting the values,
Therefore it strikes the glass pane with a velocity of 50 m/s.
Now, as mentioned in question,
The stone loses ½ velocity after striking,
Therefore, after passing through the glass pane the velocity will be,
Substituting,
This is the final velocity after passing through glass pane.
Now, Applying second kinematic equation,
Substituting the values,
Note:-
Here u = v'.
As it is mentioned in question,
That it takes further 1 second to reach the ground,
Therefore, t = 1 second.
Simplifying,
So, the Height of the glass above the ground is 30 meters.