Question

A bus decreases its speed from
180 km h to 60 km h in 5 s.
Find the acceleration of the bus.​

Answer 1

We have to make the speed in km/h and time in h

Now,

t = 5 s

➜ t = 5/3600 h

Now,

a = v-u/t

a = 60-180/(5/3600)

a = - 120/(5/3600)

a = - 120 × 3600 / 5

a = - 720

a = - 720 / 60 × 60 × 1000 { Since, we have to convert it back into km➜m and h➜s }

a = - 720 × 1000 / 3600

a = - 7200/36

a = - 200 m/s

Hence, Acceleration is -200 m/s²

Answer 2

Answer:

initial velocity=180km h = 180*5/18=50m s

final velocity=60km h=60*5/18=25m s

acceleration= v-u/t=60-50/5=2m s^2