A car requires velocity of 36 km /h in 10 sec just after the start . It takes 20 sec to stop . Calculate the acceleration in both the cases

start: a = v/t = 36km/hr/10s = 3.6 km/hr/s

you can convert km/hr to m/s if you desire the usual m/s^2 value.

to stop takes twice as long, so a = 1/2 as much.

Thank you Steve

To calculate the acceleration in both cases, we need to use the formula:

Acceleration = Change in Velocity / Time

Case 1: Car accelerating

Given:
Initial velocity (u) = 0 km/h (as the car just started)
Final velocity (v) = 36 km/h
Time (t) = 10 sec

First, we need to convert the velocities from km/h to m/s to have consistent units:

Initial velocity (u) = 0 km/h = 0 m/s
Final velocity (v) = 36 km/h = (36 * 1000) / 3600 m/s = 10 m/s

Now, we can calculate the acceleration:

Acceleration = (v - u) / t
Acceleration = (10 m/s - 0 m/s) / 10 sec
Acceleration = 10 m/s^2

Therefore, the acceleration of the car when it is accelerating is 10 m/s^2.

Case 2: Car decelerating

Given:
Initial velocity (u) = 36 km/h
Final velocity (v) = 0 km/h
Time (t) = 20 sec

Converting velocities to m/s:

Initial velocity (u) = 36 km/h = (36 * 1000) / 3600 m/s = 10 m/s
Final velocity (v) = 0 km/h = 0 m/s

Now, we can calculate the acceleration:

Acceleration = (v - u) / t
Acceleration = (0 m/s - 10 m/s) / 20 sec
Acceleration = -0.5 m/s^2

The negative sign indicates that the car is decelerating or slowing down.

Therefore, the acceleration of the car when it is decelerating is -0.5 m/s^2.