I am terrible at Physics and I'm stuck on how to do this question: A bus slows down uniformly from 66.6 km/h (18.5 m/s) to 0 km/h in 20. s. How far does it travel before stopping?

I was told to use one of these equations I'm just not sure which to use. Thanks!

vf = at + vi
x = 1/2(vf + vi)t
x = 1/2at2 + vit
vf2 = vi2 + 2ax

Question

I am terrible at Physics and I'm stuck on how to do this question: A bus slows down uniformly from 66.6 km/h (18.5 m/s) to 0 km/h in 20. s. How far does it travel before stopping?

I was told to use one of these equations I'm just not sure which to use.  Thanks!

vf = at + vi 
x = 1/2(vf + vi)t 
x = 1/2at2 + vit 
vf2 = vi2 + 2ax

anonymous · Answer

You should use the 2nd equation. x is the distance travelled (what you want to find) vf is the buses final velocity (vf=0). vi is the buses initial velocity (vi=18.5 m/s) and t is the time taken (t=20s)

anonymous · Answer

thank you!