Ask Question
3 August, 08:54

You are driving to the grocery store at 20 m/s. You are 105 m from an intersection when the traffic light turns red. Assume that your reaction time is 0.50 s and that your car brakes with constant acceleration.

(a) How far are you from the intersection when you begin to apply the brakes?

1 m

(b) What acceleration will bring you to rest right at the intersection?

2 m/s2

(c) How long does it take you to stop?

+2
Answers (1)
  1. 3 August, 09:46
    0
    (a) 95m

    (b) - 2.11m/s^2

    (c) 9.5s

    Explanation:

    (a). out of remaining 105m, for initial 0.5s I travel with constant speed:

    distace covered = 0.5s * 20m/s = 10m

    it means that I am 105-10 = 95m away from the intersection

    (b) we apply the second equation of motion

    v^2 - u^2 = 2*a*s

    so s = 95 m

    u = initial velocity = 20 m/s

    v = final velocity = 0 m/s (comes to rest)

    0^2 - 20^2 = 2*a*95

    solving for 'a'

    a = - 2.11 m/s^2

    (c)

    v-u = at

    0 - 20 = - 2.11*t

    solving for time t

    t = 9.5s
Know the Answer?
Not Sure About the Answer?
Find an answer to your question ✅ “You are driving to the grocery store at 20 m/s. You are 105 m from an intersection when the traffic light turns red. Assume that your ...” in 📘 Physics if you're in doubt about the correctness of the answers or there's no answer, then try to use the smart search and find answers to the similar questions.
Search for Other Answers