I have no idea how to do this. Anyone help?

A cyclist passes a race check point at +5.5m/s and then accelerates ata constant rate of +.55 m/s^2. The cyclist forgot to check in at the check point, and after 20s turns back around to head back. How far did the cylist move from the check point to the point of turning back?

1 answer

After 20 s, the speed increased from 5.5 m/s to
5.5 m/s + 0.55*20 = 11.5 m/s

The average speed during the 20s was
(11.5 + 5.5)/2 = 8.5 m/s

Multiply that by 20 s for the distance travelled.