Distance traveled if a driver hits the brakes

In summary, the person driving her car at 51 km/h will travel a distance of 45.1 meters before stopping if she hits the brakes at an intersection with a yellow light that lasts for 2.0 seconds and is 15 meters wide. The car's maximum deceleration is -6.0 m/s2 and it can accelerate from 51 km/h to 70 km/h in 5.7 seconds. The length of the car and the driver's reaction time are ignored in this scenario.
  • #1
Naryeth
3
0

Homework Statement


A person driving her car at 51 km/h approaches an intersection just as the traffic light turns yellow. She knows that the yellow light lasts only 2.0 s before turning to red, and she is 30 m away from the near side of the intersection (Fig. 2-29). The intersection is 15 m wide. Her car's maximum deceleration is -6.0 m/s2, whereas it can accelerate from 51 km/h to 70 km/h in 5.7 s. Ignore the length of her car and her reaction time.

If she hits the brakes, how far will she travel before stopping (in meters)?

Homework Equations


I don't know. As far as I can tell, I have two unknowns here.

The Attempt at a Solution


Lost here. As far as I can tell, all I know is that V0 = 51km/h (or 14.2m/s) and a = -6.0m/s2. Any help is appreciated, thanks in advance.
 
Physics news on Phys.org
  • #2
Naryeth said:
As far as I can tell, I have two unknowns here. All I know is that V0 = 51km/h (or 14.2m/s) and a = -6.0m/s2. Any help is appreciated, thanks in advance.
You also know that the car comes to a stop.
 

1. How does the distance traveled change if the driver hits the brakes?

When a driver hits the brakes, the distance traveled will decrease compared to if the driver did not hit the brakes. This is because the brakes cause the wheels to stop rotating and the car to slow down, reducing the overall distance traveled.

2. What factors affect the distance traveled when a driver hits the brakes?

The distance traveled when the brakes are applied is affected by several factors, including the speed of the car, the condition of the brakes, the weight of the car, and the surface of the road. These factors can impact the effectiveness of the brakes and therefore affect the distance traveled.

3. How does the speed of the car impact the distance traveled when the brakes are applied?

The higher the speed of the car, the longer the distance it will travel before coming to a complete stop when the brakes are applied. This is because the car has more momentum at higher speeds, and it takes longer for the brakes to overcome this momentum and bring the car to a stop.

4. Can the distance traveled be calculated if the driver hits the brakes?

Yes, the distance traveled can be calculated using the formula d = (v^2)/(2a), where d is the distance traveled, v is the initial velocity of the car, and a is the deceleration caused by the brakes. This formula assumes a constant deceleration and does not take into account other factors such as air resistance or tire grip.

5. How does the weight of the car affect the distance traveled when the brakes are applied?

The weight of the car plays a role in how quickly the car can come to a stop when the brakes are applied. A heavier car will require more force from the brakes to slow down and will therefore travel a longer distance before coming to a complete stop. This is why it is important to maintain proper brake maintenance for heavier vehicles.

Similar threads

  • Introductory Physics Homework Help
Replies
6
Views
699
  • Introductory Physics Homework Help
Replies
7
Views
3K
  • Introductory Physics Homework Help
Replies
29
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
12
Views
2K
  • Introductory Physics Homework Help
Replies
18
Views
6K
Back
Top