1. The problem statement, all variables and given/known data A 1200kg car moving at 20 metres per second stops in a distance of 50m when the brakes are applied. a) What is the acceleration of the car when it is braking? b) Find the force applied by the car's braking system. 2. Relevant equations For a) I used the acceleration formula: a=(velocity - initial velocity)/t Time formula from rearranging: t=s/v 3. The attempt at a solution a) t=s/v t=50/20=2.5s velocity=50/2.5=20 metres per second a=(20-0)/2.5 = 8ms(^-2) I do not know how to find the acceleration when BRAKING, and the answer claims that it is 4ms(^-2.) As for b, I believe that I am unable to attempt it seeing as I am unable to find the acceleration. Please explain how to do it! I have read through the chapter of my textbook, and am unable to understand. thank you very much!