To stop a car, first you require a certain reaction time to begin braking; then the car slows down under constant breaking decelaration. Suppose that the total distance moved by the car during these two phases is 56.7 m when its initial speed was 80.5 km/h and 24.4 m when its initial speed 48.3 km/h. What are
(a) The reaction time
(b) Magnitude of decelaration
2. Homework Equations
The Kinematical Equations
The Attempt at a Solution
Actually, my guess of what they're asking is the time between pressing the brake pedal and the brake pads squeezing in on the tyres.
So let to be the reaction time and a be the constant breaking decelaration.
u1 = 80.5 km/h = 22.36 m/s
u2 = 48.3 km/h = 13.42 m/s
Now, I thought of using s = ut + (1/2)at2, get two equations and solve them, but I have one basic question.
In the time interval I think they're asking, the car isn't decelarating. It starts decelarating after the brake pads squeeze in on the tyres. So how can I substitute to & a in the same equation?