please help me with this physics problem--desperate?

Question

A bus slows down uniformly from 69.7 km/h (19.4 m/s) to 0 km/h in 24 s. How far does it travel before stopping?

Answer 1

for the answer, you must use the equation s=ut+1/2 a(t)sqr
by substituition,
19.4 * 24 - (0-19.4)/24*2 * (24)sqr
=24(19.4 -9.7)
=24(9.7) = 232.8 m

Answer 2

v = v0 + at
Since the bus comes to a stop, v = 0
0 = v0 + at
a = -v0/t

The bus starts with a speed of 19.4 m/s and stop in 24 s so:
a = -v0/t = -19.4/24 = -0.808 m.s^2
The bus is slowing down so the acceleration should be negative.

s = v0t + (1/2)at^2 = 19.4(24) + (1/2)(-0.808)(24)^2
s = 465.6 - 242.704
s = 232.9 meters

So the bus travels 232.9 meters before it stops

Answer 3

it's just like calculating area of triangle in speed graph
please follow this link for better understanding:
http://www.physicsclassroom.com/Class/1DKin/U1L4e.html

Help to solve your case (please compare to your understanding from above site):
Distance = delta(V) * delta(time) / 2
((19.4-0)m/s*24s)/2 = 232.8m

Hope that's help