Question

A car start from rest and affairs a velocity of 40m/s in 20s. If maintain this velocity for 30s and then comes for rest in 25s calculate the acceleration of the car

Answer 1

To find the acceleration of the car, we can use the equation:

Acceleration = Change in velocity / Time taken

First, let's calculate the change in velocity during the initial 20 seconds. The car starts from rest (velocity = 0 m/s) and achieves a velocity of 40 m/s. Therefore, the change in velocity is:

Change in velocity = 40 m/s - 0 m/s = 40 m/s

Time taken in this case is 20 seconds.

Acceleration = 40 m/s / 20 s = 2 m/s²

During the next 30 seconds, the car maintains a velocity of 40 m/s. There is no change in velocity, so the acceleration during this time is 0 m/s².

Finally, during the last 25 seconds, the car comes to rest (final velocity = 0 m/s). The initial velocity in this case is 40 m/s. Thus, the change in velocity is:

Change in velocity = 0 m/s - 40 m/s = -40 m/s

Time taken is 25 seconds.

Acceleration = -40 m/s / 25 s = -1.6 m/s²

Therefore, the acceleration of the car during the different stages is:

1. An acceleration of 2 m/s² during the initial 20 seconds.
2. An acceleration of 0 m/s² during the middle 30 seconds.
3. An acceleration of -1.6 m/s² during the last 25 seconds.