A bus decreases its speed from 80 km `h^(-1)` to 60 km `h^(-1)` in 5 s. Find the acceleration of the bus.

Explanation

Here :
Initial velocity u = 80km `h^(-1)`
`=(80xx1000)/(60xx60)ms^(-1)`
`=200/9ms^(-1)`
Final velocity, `v = 60 km h^(-1)` ·
`=(60xx1000)/(60xx60)ms^(-1)`
`=50/3ms^(-1)`
time, t = 5 s
Let acceleration of the bus = a = ?
Using v = u + at, we get
`a=(v-u)/t`
`=(50/3-200/9)/5ms^(-2)`
`=1/5((150-200)/9)ms^(-1)=1/5xx(-50/9)ms^(-2)`
`=-10/9ms^(-2)=-1.11ms^(-2)`