Question

A bus decreases its speed from 72km/h to 54km/h 4sec. Find the acceleration of the bus

Answer 1

a=v-u/t
a=20-15/4
a=1.25m/s^2( convert everything into m/s )

Answer 2

Here initial velocity = 72 Km/h = 72000 / 3600
= 20 m / sec
Final velocity = 54 Km/h = 54000 / 3600
= 15 m / sec
Time taken = 4 sec

FORMULA
v - u = at
15 - 20 = a 4
- 5 / 4 = a
1.25 = - a
Therefore, deceleration of bus = 1.25 m / sec^2