Accelerations - Kinematics?

Question

Determine the stopping distances for a car with an initial speed of 89 km/h and human reaction time of 1.0s for the following accelerations.

A) a = -4.0 m/s^2

B) a = -8.0 m/s^2

Answer 1

take t =1s and vo = 89*10^3/3.6*10^3 m/s=24.72

do = 24.72m/s*1s = 24.72m

v= @t+vo = -4t+24.72=0 so t to stop = 6.18s

distance = -1/2*4*(6.18)^2 +24*72*6.18+24.72=101.1m

You can do the same putting -8 instead of -4

Answer 2

Anybody who makes four posts about subject matter like this is obviously copping out from doing their homework.  

Forsooth, young 'un.... get a grip and paddle your own canoe.