You are driving to the grocery store at 14 m/s. You are 115 m from an intersection when the traffic light turns red. Assume that your reacti

Question

You are driving to the grocery store at 14 m/s. You are 115 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. How far are you from the intersection (in m) when you begin to apply the brakes

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Thiên Di 1 week 2021-07-21T22:28:08+00:00 1 Answers 1 views 0

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    2021-07-21T22:30:01+00:00

    Answer:

    111.5 m

    Explanation:

    Given that You are driving to the grocery store at 14 m/s. You are 115 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. 

    Use first equation of motion

    V = U – at

    Since the car is going to rest, V = 0 and a = negative

    0 = 14 – a × 0.5

    0.5a = 14

    a = 14 /0.5

    a = 28 m/s^2

    Let us use second equation of motion

    S = Ut – 1/2at^2

    S = 14 × 0.5 – 0.5 × 28 × 0.5^2

    S = 7 – 3.5

    S = 3.5 m

    115 – 3.5 = 111.5

    Therefore, you are 111.5 metres from the intersection (in m) when you begin to apply the brakes.

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