Should the driver make a run for it at an intersection with a yellow light?

• Pindle
In summary, the conversation discusses a scenario where a person is driving at 50km/h and approaches an intersection with a yellow light that lasts 2 seconds before turning red. The person is 30m away from the intersection and has to decide whether to stop or make a run for it. The intersection is 12m wide and the car's maximum deceleration is -6m/s^2. The car takes 7 seconds to accelerate from 50km/h to 70km/h. The conversation also mentions ignoring the length of the car and the driver's reaction time. The main question is whether 2 seconds is enough time for the car to stop or if the driver should make a run for it.
Pindle

Homework Statement

A person driving her car at 50km/h approaches an intersection just as the traffic light turns yellow. She knows that the yellow light lasts only 2s before turning red, and she is 30m away from the near side of the intersection. Should she try to stop, or should she make a run for it? The intersection is 12m wide, and her car's max. deceleration is -6m/s^2. Also her car takes 7s to accelerate from 50km/h to 70km/h. Ignore the length of the car and her reaction time.

I don't know.

The Attempt at a Solution

First, how much is the acceleration, when we say: if you hit the gas pedal in that car, you can accelerate from 50 to 70 km/h in 7 seconds?

You approach an intersection with a given initial velocity, and you have to cover a given distance, with a certain amount of acceleration. Will 2 seconds be enough time? Look for a formula that includes those variables.

Last edited:

Based on the given information, it would be safer for the driver to stop at the yellow light rather than trying to make a run for it. This is because the yellow light only lasts for 2 seconds and the car is 30m away from the intersection, which may not be enough time and distance for the car to safely accelerate to 70km/h and cross the intersection. Additionally, the car's maximum deceleration is -6m/s^2, which may not be enough to stop the car in time before reaching the intersection. It would be better to err on the side of caution and stop at the yellow light to avoid any potential accidents.

1. What is Kinematics?

Kinematics is the study of motion and its causes, without considering the forces that cause the motion.

2. What are the three main types of kinematics equations?

The three main types of kinematics equations are displacement equations, velocity equations, and acceleration equations. These equations use the variables of time, displacement, velocity, and acceleration to describe the motion of an object.

3. How do you calculate displacement?

Displacement is calculated by subtracting the initial position from the final position of an object. It can be represented by the equation Δx = xf - xi, where Δx is displacement, xf is final position, and xi is initial position.

4. What is the difference between speed and velocity?

Speed is a measure of how fast an object is moving, while velocity is a measure of how fast an object is moving in a specific direction. Speed is a scalar quantity, meaning it has only magnitude, while velocity is a vector quantity, meaning it has both magnitude and direction.

5. What is the equation for acceleration?

The equation for acceleration is a = Δv/Δt, where a is acceleration, Δv is change in velocity, and Δt is change in time. Acceleration is a measure of how quickly an object's velocity changes.

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