Question

1. At the starting gun a runner accelerates from rest at 2.0 m/s2 for 2.2 s. What is the runners speed 1.2 s after she starts running?

2. A skier starts from rest and accelerates down a slope at 2.2 m/s2 . How much time is required for the skier to reach a speed of 9.0 m/s ?

Answer 1

Explanation:

1. Given:

v₀ = 0 m/s

a = 2.0 m/s²

t = 1.2 s

Find: v

v = at + v₀

v = (2.0 m/s²) (1.2 s) + 0 m/s

v = 2.4 m/s

2. Given:

v₀ = 0 m/s

v = 9.0 m/s

a = 2.2 m/s²

Find: t

v = at + v₀

9.0 m/s = (2.2 m/s²) t + 0 m/s

t ≈ 4.1 s