Question

a bus is traveling at a speed of 72km/h brakes are applied so as to produce a uniform acceleration -0.3m/s2 find how far bus brought to rest .

Answer 1

First of all we have to convert 72 Km/Hr into m/s.
Hence 72 × 5/18 = 20 m/s.
Here U= 20 m/s , A = -0.3 m/s^2 and the bus is being brought to rest hence V = 0 m/s.
Using the formula,
V= U + AT
0 = 20 + (-0.3)×T
0 = 20 - 0.3T
Transposing 0.3T to left
0.3T = 20
Transposing 0.3 to Right
T = 20/0.3 = 200/3 = 66.6 sec.