Max Reaction Time to Avoid Obstacle 95m Away

  • Thread starter rrosa522
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In summary, the driver has a reaction time of 0.5 seconds, and it will take her 0.5 seconds to travel the remaining 0.5 meters.
  • #1
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Homework Statement


a vehicle is traveling at 25m/s. its breaks provide an acceleration of -3.75m/s^2. What is the drivers maximum reaction time is she is to avoid hitting an obstacle 95.0m away?

Homework Equations


D=vi(t) +1/2a(t)^2
3. The Attempt at a Solution
D=95m
vi=25 m/s
a=-3.75m/s ^2
I plugged it into the equation D=vi(t) +1/2a(t)^2 and i got -2.02, which is obviously wrong

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  • #2
rrosa522 said:

Homework Statement


a vehicle is traveling at 25m/s. its breaks provide an acceleration of -3.75m/s^2. What is the drivers maximum reaction time is she is to avoid hitting an obstacle 95.0m away?

Homework Equations


D=vi(t) +1/2a(t)^2

The Attempt at a Solution


D=95m
vi=25 m/s
a=-3.75m/s ^2
I plugged it into the equation D=vi(t) +1/2a(t)^2 and i got -2.02, which is obviously wrong
In your attempt you've assumed that the braking begins immediately when there are still 95 m to the obstacle. This won't be the case. During the time it takes for the driver to react the vehicle continues to travel at its initial speed. Only after the driver reacts does the braking begin.

There are two intervals to be concerned about. The first interval is the period where the driver is deciding that she must brake and take action (the reaction time). The second is where the actual deceleration takes place. I suggest that you begin with the second interval and determine what the actual stopping distance is once the braking begins.
 
  • #3
Your problem is that it doesn't take the entire 95 meters to stop. In other words, this person will have room left over. That's where you figure in the reaction time.

You'll need to use a formula that relates velocity, acceleration, and distance. Hint: the initial velocity is 25 m/s, and the final velocity is 0 m/s.

After you find the distance traveled during deceleration, then you know how much distance is left over. Then you find out how long it takes to travel that distance going 25 m/s, and you'll know how much time the driver has to react.
 

1. What is the purpose of studying max reaction time to avoid obstacles?

The purpose of studying max reaction time to avoid obstacles is to understand how quickly a person can react and make decisions in potentially dangerous or unexpected situations. This can help inform safety measures and improve response times in emergency situations.

2. How is max reaction time to avoid obstacles measured?

Max reaction time to avoid obstacles is typically measured by timing a person's response to a sudden stimulus, such as a flashing light or loud noise, and their subsequent movement to avoid the obstacle. This time is then recorded and analyzed.

3. Are there factors that can affect a person's max reaction time to avoid obstacles?

Yes, there are several factors that can affect a person's max reaction time to avoid obstacles, such as age, physical fitness, distractions, and level of experience. These factors can impact a person's ability to process information and make quick decisions.

4. What is considered a good max reaction time to avoid obstacles?

The average human reaction time is around 250 milliseconds, but this can vary depending on the individual and the situation. In general, a good max reaction time to avoid obstacles would be considered anything under 500 milliseconds.

5. How can knowledge of max reaction time to avoid obstacles be applied in real-world situations?

Knowledge of max reaction time to avoid obstacles can be applied in various real-world situations, such as designing safer roads and traffic systems, improving safety protocols in hazardous work environments, and developing training programs for emergency response teams. It can also help individuals become more aware of their own reaction times and potentially improve their decision-making skills in critical situations.

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