Question

A ball is thrown straight up with a speed of 3\frac{m}{s}, and it hits the ground with a speed of 15\frac{m}{s}. How tall is the tower? Ignore air resistance, and answer in meters.

Answer 1

Height of tower is 11 meters

Step-by-step explanation:

We have equation of motion v² = u² + 2as

Initial velocity, u = 3 m/s upwards

Acceleration, a = -9.81 m/s² downwards

Final velocity, v = -15 m/s downwards

Substituting

v² = u² + 2as

(-15)² = 3² + 2 x -9.81 x s

s = -11 m that is downward

Form the initial position it travels 11 meter downward.

Height of tower is 11 meters