Question

At the starting gun a runner accelerates from rest at 1.7 m/s^2 for 2.2 What is the runner's speed 1.3 s after she starts running?

Answer 1

The runner´s speed is 2.2 m/s after 1.3 s.

Step-by-step explanation:

The acceleration is the variation of velocity over time. If the acceleration is constant, then:

dv/dt = a

Separating variables:

dv = a · dt

integrating from initial velocity (v0) to v and from t = 0 to t:

v - v0 = a · t

v = v0 + a · t

Then usign this equation, we can calcualte the speed at t = 1.3 s:

v = 0 m/s + 1.7 m/s² · 1.3 s

v = 2.2 m/s

The runner´s speed is 2.2 m/s after 1.3 s.