Question

A ball is thrown vertically upward at 100 m/s and the height of the tower is 100 m at what speed will it strike the ground

Answer 1

The ball thrown vertically upward will eventually come back to the starting point, travelling with the same speed, downwards.

Now, we wish to find the final speed, given the initial speed, acceleration and distance to traverse. This calls for the equation of motion:

v² = u² + 2aS

Substituting the values, we get:

v² = (100)² + 2 * 10 * 100 (m/s)²

v² = 12000 (m/s)²

v = 20√(30) m/s