A soccer ball is kicked straight up in the air with an initial velocity of 17 m/s and rises to a height of 14.7 m before beginning to fall back down. How long (in total) is the soccer ball in the air?

3.4 s

Explanation:

Given:

Δy = 0 m

v₀ = 17 m/s

a = -10 m/s²

Find: t

Δy = v₀ t + ½ at²

0 m = (17 m/s) t + ½ (-10 m/s²) t²

0 = 17 m/s − (5 m/s²) t

t = 3.4 s

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.