Question

A bus decreases its speed from 80km/h to 60 km/h in 5 sec . Fing the acceleration of a bus .

Answer 1

Hello friend,

As per question,
Initial velocity, u = 80 km/h
Final velocity, v = 60 km/h
Time, t = 5 sec
We must take the Time in hours,
Since
1 hour = 3600 sec
1 sec = 1/3600 hour
Similarly,
5 sec = 5/3600 hour
On simplying we get,
5 sec = 1/720 hour

Now,
Acceleration,
$= \frac{(v - u)}{t} \\ = \frac{(60 - 80)}{1/720} \\ = \frac{ - 20}{1/720}$
-20 * 720
-14400 km/h

So,
Acceleration = - 14400 km/h

Since,
The acceleration is negative, it's called retardation.
Retardation = 14400 km/h