A car starts at 80 m/s but sees a cop and hits the brakes slowing down to 50 m/s in 2 sec.

-15m/s/s

Explanation:

Acceleration = change in speed/ change in time

The change in speed is calculated by subtracting the initial speed from the final speed, so the change in speed is: 50 - 80 = -30m/s. The change in time is 2 - 0 = 2.

So the car acceleration is -30/2 = -15m/s/s

It is negative because it is decelerating.

Hope this helped!

think its the third option