Question

A bus decereases its speed from 80km/h to60km/h in 5minutes .find its acceleration

Answer 1

Initial velocity u = 80 km h-1



Final velocity u = 60kmph



Time  t= 5s   ,      a =?



The acceleration of bus is -1.11 m s-2

Answer 2

Initial Velocity of bus = 80km/h = 80×5/18 m/s
= 200/9 m/s

Final Velocity if bus = 60km/h = 60×5/18 m/s
= 150/9 m/s

Time =5minutes = 5×60 seconds = 300second

Acceleration
=( final velocity-initial velocity)/Time

= {(150/9)-(200/9)}/300

= -50/9/300

= -1/54 m/s²

Acceleration of body is -1/54 m/s.