A porsche reaches a velocity of 42.0 km/h from a standing start in 15.5 s. What distance does it cover in doing so?

Question

stormfire1 · Answer

First, I'd convert km/h to m/s:
42000m/3600s = 11.66 m/s

The problem doesn't mention acceleration so you can assume it's constant...so the kinematic equations for constant acceleration will work just fine.

$$Xf = X i + (Vi + Vf)t$$Plug in what you know...
$$Xf = 0m + (0m/s + 11.66m/s)15.5s$$$$Xf = 180.73m$$

anonymous · Answer

It does include acceleration. The term standing start means that the initial velocity was zero. Final velocity is 42 km/h. The acceleration is easy to find since your given the time. 

I have already solved this question elsewhere on this website.