posted by James on .
A runner of mass 51.5 kg starts from rest and accelerates with a constant acceleration of 1.35 m/s2 until she reaches a velocity of 5.7 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.)
(a) How far has she run after 64.7 s?
(b) What is the velocity of the runner at this point?
do this in two parts:
distance running speeding up
vf=vi+2at solve for t, then
distance= vf/2 * t
second runnign at constant velocity
add the distances.