A sports car moving at 30m/s comes to a stop in 4.2s. What was the acceleration of the car?
I'm not great at Physics....but....I might be able to answer a few of these
Acceleration = Change in Velocity / Change in Time = [ 30 - 0 ] / [ 0 - 4.2 ] =
[ 30m/s] / [ - 4.2 s] ≈ - 7.14 m/s^2
+33 
