Question

PLEASE HELP

When you see a traffic light turn red, you apply the brakes and stop with constant acceleration.

If your initial speed was 23 m/s , what is your average speed during braking?
Express your answer to two significant figures and include the appropriate units.

Answer 1

Let the initial velocity be u = 23 m/s

Let the final velocity be v.

Vehicle stops finally, therefore v = 0 m/s

Here during the braking, vehicle decelerates with constant acceleration, thus the change in velocity is linear from initial velocity to final velocity.

for the Given condition:

Write the expression for the average speed
`V_(avg)`

`V_(avg) =  (u+v)/(2)\\`

Substitute the values in the above expression.

`V_(avg) = (23+0)/(2)\\              = 11.5 m/s`

Hence, the average speed during braking is 11.5 m/s