Physics Dynamics

Question

A car is initially moving at 15.3 m/s when your hit the brakes and the car begins to slow down. The car has a mass of 532 kg and the coefficient of friction between the tires and the road is 0.23. What is the time needed to stop the car and how much ground does it cover during this process?

I already found the distance, just need help with time

Answer 1

Use the kinematics equations at your disposal:

v_f = v_i + at

Δx = v_it + ¹/₂at²

v_f² = v_i² + 2aΔx

Δx = ¹/₂(v_i + v_f)t

Select the equation that solves for the displacement of the car (that eliminates one of them), and includes the variables that you already have values for.

Remember that the only scalar quantity is time, so all of your other quantities should have either a positive or negative sign to account for the direction.