Physics 11

The brakes on a car permit it to decelerate at the rate of -8.0m/s^2. How much distance is required to stop this car when it is travelling 60.0km/hr?

The answer given is 173.6m

I solved it this way
60km/h = 16.667m/s
A=V/T 16.667m/s / -.80m/s^2 = 20.834 seconds
D=RT 16.667m/s x 20.834seconds = 347.24m

This is wrong and I do not understand why. Am I doing it right or is the answer wrong?

  1. 👍
  2. 👎
  3. 👁
  1. The last equation....

    distance= rate/time. You need the average velocity, not the initial. Average here is 1/2 the initial.

    1. 👍
    2. 👎
    👤
    bobpursley
  2. Hi, I'm very familiar with math. I'm 11, and I'm the king of math of my class. Your answer is twice as much as the given answer, David. Hey there, you got the second equation wrong. For the divisor you are supposed to have the time, not the acceleration. Try solving for the time by knowing about integrals (F(a)=v; F(v)=t; this is tricky, I hope it works).

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. physics

    A 1000 kg car traveling is at 40.0 m/ s. To avoid hitting a second car the driver slams on his brakes. The brakes provide a constant friction force of 8000 N. ( a) Find the minimum distance that the brakes should be applied in

  2. Physics

    Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 3.6 m/s2 for 4.5 seconds. It then continues at a constant speed for 7.3

  3. Physics

    A car slows down from 108 km/h to 90 km/h over the course of 4 s and 0.1 km. The force of the brakes was 1000 N. What is the work done by the brakes on the car?

  4. physics

    Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 4.6 m/s2 for 4.4 seconds. It then continues at a constant speed for 8.5

  1. physics

    a)Two cars are traveling along a straight line in the same direction, the lead car at 24.5m/s and the other car at 29.6m/s. At the moment the cars are 41.6m apart, the lead driver applies the brakes, causing her car to have an

  2. Physics

    A car with good tires on a dry road can decelerate at about 5.0m/s/s when braking. If the car is traveling at 55miles/hour, how much time does it take the car to stop? 55 mph = 80.7 ft/s = 24.6 m/s Divide the initial speed by the

  3. physics

    A car starts from rest and travels for 6.0s with a uniform acceleration of 2.7m/s ^2. The driver then applies the brakes, causing a uniform acceleration of -2.0m/s^2. If the brakes are applied for 2.0s, determine each of the

  4. physics

    A car starts from rest and travels for 6.0 s with a uniform acceleration of +2.4 m/s2. The driver then applies the brakes, causing a uniform acceleration of −1.0 m/s2. If the brakes are applied for 3.0 s, determine each of the

  1. calculus

    The driver of a car traveling at 60 ft/sec suddenly applies the brakes. The position of the car is s(t) = 50t - 2t2, t seconds after the driver applies the brakes. How many seconds after the driver applies the brakes does the car

  2. physics

    A car and driver weighing 7750 N passes a sign stating “Bridge Out 28.5 m Ahead.” She slams on the brakes, and the car decelerates at a constant rate of 10.6 m/s2 . The acceleration of gravity is 9.8 m/s2 . What is the

  3. physics

    Q: Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 5.7 m/s2 for 3.2 seconds. It then continues at a constant speed for 8.8

  4. Physical science

    A car moving at 50km/hr skids 15m with locked brakes. How far will the car skid (with locked brakes if the car moves at 100km/hr assume that the mass of the car is 500kg

You can view more similar questions or ask a new question.