Question

A runner of mass 53.0 kg starts from rest and accelerates with a constant acceleration of 1.30 m/s2 until she reaches a velocity of 6.1 m/s. She then continues running with this constant velocity. (Take the direction the runner is going to be the positive direction. Indicate the direction with the sign of your answer.)
How far has she run after 60.7 s?

Answer 1

You can break this into two parts, the first where velocity is increasing, the second where velocity is constant.

Part 1: Increasing velocity
To find the time it takes to accelerate from rest to 6.1 m/s use
\[v=v_0+at\]
Then use that time to find the displacement
\[d=v_0t+\frac{ 1 }{ 2 }at^2\]

Part 2: Constant velocity
Subtract the time above from 60.7 s, then use \[d=vt\]

Answer 2

Thank You!!