Question

A car traveling due east at 20 m/s reverses its direction over a period of 10 seconds so that it is now traveling due west at 20 m/s. What is the direction of the car’s average acceleration over this period?

Answer 1

west

Step-by-step explanation:

We can take east as positive (+) direction and west as negative (-) direction. With this sign convention, we have:

- Initial velocity: u = +20 m/s (due east)

- Final velocity: v = -20 m/s (due west)

- Time taken to change velocity: t = 10 s

Therefore, we can use the formula for the acceleration to calculate the car's acceleration:

`a=(v-u)/(t)=((-20 m/s)-(+20 m/s))/(10 s)=(-40 m/s)/(10 s)=-4 m/s^2`

And the negative sign means the direction of the car's acceleration is west.