A ball is thrown vertically upwards. It goes to a height 20 m and then returns to the ground. Taking acceleration due to gravity g to be `10 "m s"^(-2)` ?, find the final velocity of ball on reaching the ground

Explanation

To find the final velocity of the ball when it reaches the ground after being thrown vertically upwards to a height of 20 m, we can use the equations of motion. Here’s a step-by-step solution:

### Step 1: Identify the known values
- Height (h) = 20 m
- Acceleration due to gravity (g) = 10 m/s²
- Initial velocity (u) at the maximum height = 0 m/s (when it reaches the maximum height before falling back down)

### Step 2: Use the third equation of motion
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