A ball is projected 125 meters straight upward and then falls the same distance back to its starting point. Neglecting air resistance, its total time in the air is about
A)5 s.
B)10 s.
C)15 s.
D)more than 20 s.

Question

Quizplus · Accepted Answer

The time taken for a ball to reach its maximum height is given by the formula:

t = √(2h/g)

where h is the maximum height reached and g is the acceleration due to gravity (9.8 m/s^2).

In this case, the maximum height reached is 125 meters, so

t = √(2 x 125/9.8) = 5 s.

The total time in the air is twice this time, since the ball falls back to its starting point, so the total time is

2 x 5 s = 10 s.

Therefore, the best choice is B).

A Ball Is Projected 125 Meters Straight Upward and Then