Kinematic Problem: Solve Traffic Light Stop Distance

  • Thread starter ireneooi
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In summary, a motorist traveling at 13 m/s approaches traffic lights which turn red when he is 25m away from the stop line. His reaction time is 0.7s and the car cannot slow down at a rate of more than 4.5 ms-2. Using the kinematics equations available, the car will stop 27.025m away from the stop line and it will be on the same side as the stop line. The acceleration mentioned in the problem is the deceleration of the car, with a value of -4.5 ms-2.
  • #1
ireneooi
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Hi,really need help with this question.
A motorist traveling at 13 m/s aprroaches traffic lights which turn red when he is 25m away from the stop line.His reaction time(i.e. the interval between seeing the red light and applying the brakes)is 0.7s and the condition of the road and his tyres is such that the car cannot slow down at a rate of more than 4.5 ms-2.If he brakes fully,how far from the stop line will he stop,and on which side of it?

Thanks in advance!
 
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  • #2
Please show us some effort from u! It is not that we cannot give you help.
 
  • #3
use the very simple kinematics equations available. Manipulate them to et an answer. If you have a more specific probem in this question, please state it. Nobody will solve your problem for you.

[tex] V^2 = {V_o}^2 + 2ad [/tex]
[tex] d = V_o t + \frac{1}{2} at^2 [/tex]
[tex] V = \frac{d}{t} [/tex]

Regards,

Nenad
 
  • #4
Oh,sorry,I actually just have one problem,which is the acceleration part of the question.Can anyone just explain what it means?Thanks.
 
  • #5
It's a deceleration.With constant acceleration [itex] a=-4.5ms^{-2} [/itex]...

Daniel.
 

1. What is a kinematic problem in relation to traffic light stop distance?

A kinematic problem in relation to traffic light stop distance refers to a physics problem that involves calculating the distance a vehicle needs to stop at a traffic light, taking into account factors such as initial velocity, acceleration, and the distance between the vehicle and the traffic light.

2. What information is needed to solve a kinematic problem for traffic light stop distance?

To solve a kinematic problem for traffic light stop distance, you will need to know the initial velocity of the vehicle, the acceleration of the vehicle, and the distance between the vehicle and the traffic light. You may also need to know the time it takes for the vehicle to stop or the maximum deceleration of the vehicle.

3. How does the distance between the vehicle and the traffic light affect the stop distance?

The distance between the vehicle and the traffic light directly affects the stop distance. The greater the distance, the longer it will take for the vehicle to come to a complete stop. This is because the vehicle will need to travel a greater distance to reach the traffic light, and therefore require more time to decelerate.

4. How does the initial velocity of the vehicle impact the stop distance?

The initial velocity of the vehicle also plays a role in determining the stop distance. The greater the initial velocity, the longer it will take for the vehicle to come to a complete stop. This is because the vehicle will have more kinetic energy to dissipate, requiring a longer distance to decelerate.

5. What is the significance of solving kinematic problems for traffic light stop distance?

Solving kinematic problems for traffic light stop distance is important for understanding the physics behind stopping a vehicle and can help in determining safe stopping distances. It can also be useful in designing traffic signals and intersections to ensure safe and efficient traffic flow.

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