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

Explanation

Initial speed of the bus `(u) = 80 km h ^(-1)`
`= ( 80 xx 1000)/( 3600) ms ^(-1)`
`= (800)/(36) ms ^(-1)`
Final speed of the bus `(v) =60 kmh^(1)`
`= (60 xx 1000)/( 3600) ms ^(-1)`
`= (600)/(36) ms ^(-1)`
Acceleration `= (u-v)/(t) = ((600)/(36)- (800)/(36))/( 5) = (-200)/( 36) xx 1/5 =- (10)/(9) ~~-1.11 ms ^(-2)`
The acceleration of the bus is `-1.11 ms ^(-2)`
`(or -1.11 ms ^(-2))`