How far does the car travel in total before stopping

Question

A driver traveling at 10.9m/s and has a reaction time of 0.3 seconds.

Answer 1

So this will be a 3-step problem.

1. Step one: before reaction.
2. Before the driver reacts, they will continue at 10.9 m/s.
3. They will cover a distance, d₁ that you can solve using the equation v = d/t, where t is the reaction time.
4. Step two: after reaction (assuming you meant a = -3.8m/s² - don't forget the square in the units, it's important)
5. v_i = 10.9 m/s
6. v_f = 0 m/s (because it's stopping)
7. a = -3.8 m/s² (we use negative because it's decelerating, so the value needs to be the opposite sign of the velocity)
8. d is the unknown
9. You need an equation that relates these 4 variables: v_f² = v_i² + 2ad
10. Solve for this d, which we can call d₂
11. Step 3: combine your answers
12. The total distance covered before stopping will equal the sum of the two distances you've calculated.