AP Physics

posted by .

To stop a car, you require first a certain reaction time to begin braking. Then the car slows under the constant braking deceleration. Suppose that the total distance moved by your car during these two phases is 56.7 m when its initial speed is 82.5 km/h, and 24.4 when the initial speed is 50.3 km/h. What is your reaction time? What is the magnitude of the deceleration?

  • AP Physics -

    Let tr be reaction time.

    The distance traveled during the reaction time is vi*tr, so the distance traveled during stopping is (distancetotal-vi*tr). Now you have an equation...
    Vf^2=Vi^2 + 2ad Use that. I will set up one equation for you, you do the second, and solve for tr, and a.

    1) 0=24.4^2 + 2a (56.7-24.4tr)
    2) ....

  • AP Physics -

    I still don't get how to get the time it takes to decelerate from 82.5 to 50.3 km/h, i know its a constant deceleration, but i know how to find either the deceleration or the time

  • AP Physics -

    I still don't get how to get the time it takes to get from 82.5 to 50.3 km/h, i know its a constant deceleration, but i don't know how to get the time

  • AP Physics -

    I still don't get how to get the time it takes to get from 82.5 to 50.3 km/h, i know its a constant deceleration, but i don't know how to get the time it takes to decelerate

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    To stop a car, first you require a certain reaction time to begin braking. Then the car slows down at a constant rate. Suppose that the total distance moved by your car during these two phases is 56.7 m when its initial speed is 85.0 …
  2. Physics

    To stop a car, you require first a certain reaction time to begin braking. Then the car slows under the constant braking deceleration. Suppose that the total distance moved by your car during these two phases is 56.7 m when its initial …
  3. physics

    Proper design of automobile braking systems must account for heat buildup under heaving braking. Calculate the thermal energy dissipated from brakes in a 1460-kg car that descends a 15.5° hill. The car begins braking when its speed …
  4. college math

    Braking distance The braking distance y in feetthat it takes for a car to stop on wet ,level pavement can be estimated by y = 1/9 x^2, where the x is the speed of the car in miles per hour Find the speed associated with with each braking …
  5. Physics

    A CAR HAS A MASS OF 1200KG TRAVELLING ON A LEVEL ROAD. THE CAR DECELERATED AT A RATE OF 10M/S^2 TILL THE CAR STOPPED. iT HAS TO OVERCOME A TOTAL RESISTANCE OF 400N WHILE BRAKING. (I) CALCULATE THE BRAKING FORCE OF THE CAR (II) WHAT …
  6. Physics

    The braking distance of a car is 29m. If the speed of the car is increased by 45%, what is the car's new braking distance?
  7. physics

    Proper design of automobile braking systems must account for heat buildup under heavy breaking. Calculate the thermal energy dissipated from brakes in a 1500 kg car that descends a 17° hill. The car begins braking when its speed is …
  8. Physics

    Proper design of automobile braking systems must account for heat buildup under heaving braking. Calculate the thermal energy dissipated from brakes in a 1360-kg car that descends a 13.5° hill. The car begins braking when its speed …
  9. Physics

    You are driving down the highway late one night at 20 m/s when a deer steps onto the road 35 m in front of you. Your reaction time before stepping on the brakes is 0.50 s , and the maximum deceleration of your car is 10 m/s2 . How …
  10. Physics

    A driver in a car, originally moving at 13.1 m/s, applies the brakes until the car comes to a stop. The car moves a distance of 34.1 m while braking. How much time did it take for the car to stop?

More Similar Questions