Question

a bus decreases its speed from 80 kilometre per hour to 60 km per hour in 5
seconds find its retardio
plz explane​

Answer 1

Given:-

• Initial velocity ,u = 80km/h
• Final velocity ,v = 60km/h
• Time taken ,t = 5s

To Find:-

• Retardation ,a

Solution:-

According to the Question

We have to calculate the retardation of the bus .

Firstly we change the unit here .

Initial velocity ,u = 80×5/18 = 400/18 m/s

Final velocity ,v = 60×5/18 = 300/18 m/s

Now, we now that rate of change in velocity is called acceleration.

Negative Acceleration is called retardation.

• a = v-u/t

where

• v is the final velocity
• a is the acceleration
• u is the initial velocity
• t is the time taken

Substitute the value we get

$:\implies$ a = (300/18-400/18)/5

$:\implies$ a = (-100/18)/5

$:\implies$ a = -100/90

$:\implies$ a = -10/9 or -1.11

• Hence, the retardation of the bus is 10/9 m/s².

Answer 2

Answer:

a= -4 m/s²

Explanation:

the the bus is moving with 80 kilometre per hour therefore its initial velocity is 80 km per hour then after that it comes to 60 kilometre per hour so we can say that final velocity is 60 kilometre per hour while the time taken is 5 seconds, therefore by applying Newton's first equation of motion. we will get -4 metre per second², the negative sign shows deceleration/retardation.