ball is thrown vertically upwards with a velocity of 20 m/s from the top of a building of height 40 m from the ground.
(i) How high the ball reaches?
(ii) How long will it take to reach the ground ?
(iii) What is the speed at which it strikes the ground?

Explanation

To solve the problem step by step, we will break it down into three parts as per the questions asked.

### Given Data:
- Initial velocity of the ball, \( u = 20 \, \text{m/s} \) (upwards)
- Height of the building, \( h_b = 40 \, \text{m} \)
- Acceleration due to gravity, \( g = 10 \, \text{m/s}^2 \)

### (i) How high does the ball reach?
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