A cars velocity changes from 100 m/s to 20 m/s in 40 seconds. What is the acceleration of the car?

Acceleration=a = unknown, since we are to find the velocity.

Final velocity=100m/s=v

Initial velocity=20m/s = u

Time=40seconds.

Mathematically:

a=v-u/t

substituting the givens into the equation.

a = 100-20/40

a=80/40

a=2m/s²