Physics

posted by .

A driver of a car going 90.0km/h suddenly sees the lights of a barrier 40.0 metres ahead. It takes the driver 0.75 seconds before she applies the brakes, and the average acceleration during braking is -10.0 m/s squared. Does the car hit the barrier?SHow all your work. (2 parts)

  • Physics -

    V = 90km/h = 90km/h / 3600s/h = 0.025km/s = 25m/s.

    d = 25m/s * 0.75s = 18.75m = Distance
    traveled before brakes are applied.

    d = 40 - 18.75 = 21.25m = max stopping
    dist.

    Vf^2 = Vo^2 + 2ad = 0,
    (25)^2 + 2(-10)d = 0,
    625 - -20d = 0,
    -20d = -625,
    d = -625 / -20 = 31.25m = Distance traveled after brakes are applied.

    The car will hit the barrier, because it was required to stop within 21.25m
    after the brakes are applied.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    What is the maximum speed at which a car could be moving and not hit a barrier 35.0 m ahead if the average acceleration during braking is -10.0 m/s2 and it takes the driver 0.90 s before he applies the brakes?
  2. Physics

    What is the maximum speed at which a car could be moving and not hit a barrier 35.0 m ahead if the average acceleration during braking is -10.0 m/s2 and it takes the driver 0.90 s before he applies the brakes?
  3. physics

    The driver of a car going 90.0 km/h suddenly sees the lights of a barrier 35.0 m ahead. It takes the driver 0.75 s to apply the brakes, and the average acceleration during braking is -10.0 m/s2. (b) What is the maximum speed at which …
  4. physics

    A car starts from rest and travels for t1 seconds with a uniform acceleration a1. The driver then applies the brakes, causing a uniform acceleration a2. If the brakes are applied for t2 seconds, determine the following. Answers are …
  5. Physics

    A driver of a car going 95.0 km/h suddenly sees the lights of a barrier 39.0 m ahead. It takes the driver 0.95 s before he applies the brakes, and the average acceleration during braking is -10.0 m/s2. What is the maximum speed at …
  6. Physics

    A driver of a car going 95.0 km/h suddenly sees the lights of a barrier 39.0 m ahead. It takes the driver 0.95 s before he applies the brakes, and the average acceleration during braking is -10.0 m/s2. What is the maximum speed at …
  7. Physics

    a driver of a car going 95.0km/h suddenly sees the lights of a barrier 35.0 m aheadd. It takes the driver 95 s before he applies the breaks, and the average acceleraion during breaking is -10.om/s/s does the car hit the barrier?
  8. physics

    A car is traveling at 20.8 m/s when the driver sees a dog run out into the street. From the time the driver applies the brakes, it takes 3.58 s for the car to come to a stop. What is the average acceleration during that period?
  9. Physics

    A driver of a car going 90 km/h suddenly sees the lights of a barrier 40.0 m ahead. It takes the driver 0.75 s to apply the brakes, and the average acceleration during braking is -10 m/s2. (a) Compute for the total displacement of …
  10. Physics

    The driver of a car is going 90 km/hr suddenly sees a barrier40m ahead. It takes the driver .75 sec to apply the brakes, and the average acceleration during braking is -10m/s^2. Will the car hit the barrier and use calculation to show …

More Similar Questions