# Stopping Distance + Reaction Time Problem -> Physics beginner

• MyFinalRegret
In summary, the conversation discusses a physics problem involving stopping distance and reaction time for a car traveling at a speed of 80km/h and decelerating at 8m/s/s. The final stopping distance is determined to be 41.97m using the equations V1 = V0 + at and D = V0t + 1/2at^2. The student also mentions using another kinematic equation to simplify the solution process.
MyFinalRegret
Stopping Distance + Reaction Time Problem ---> Physics beginner

## Homework Statement

A car is traveling at 80km/h, and brakes with a reaction time of .5 seconds. The car decelerates at 8m/s/s, determine the stopping distance of the car.

## Homework Equations

- V1 = V0 + at
- D = V0t + 1/2at2

Where:
V1 = Final Speed
V0 = Initial Speed
A = Acceleration
T = Time
D = Distance

## The Attempt at a Solution

Distance Traveled before Braking:
80km/h = 22.22m/s

0.5 * 22.22m/s = 11.11 m

Distance After Reaction:
V1 = V0 + at
0 = 22.22 - 8t
t = 2.7775 seconds

D = V0t + 1/2at2
D = 22.22 * 2.7775 - [(8 * 2.77752)/2]
D = 30.86m

Total Stopping Distance = 11.11m + 30.86m
= 41.97 m

Notes
I am only beginning to learn some basic concepts of physics in class, so I'm not entirely sure about the equations.

My teacher has provided no answer sheet to the question, and I am finding it hard to grasp the method of solving the question without a step by step example from a similar question.

I'd greatly appreciate it if anyone could let me know if I am right, or how to do it if I am wrong.

Thanks :D

Last edited by a moderator:

Thank you for the help and additional formulas !
Now I'll be able to do my other sums :D

## 1. What is stopping distance?

Stopping distance is the distance a vehicle travels from the moment the brakes are applied to the moment the vehicle comes to a complete stop.

## 2. What is reaction time?

Reaction time is the amount of time it takes for a person to respond to a stimulus, in this case, the moment the driver perceives a need to stop and applies the brakes.

## 3. How is stopping distance calculated?

Stopping distance is calculated by adding the reaction distance (distance traveled during reaction time) and the braking distance (distance traveled while braking) together.

## 4. How does speed affect stopping distance?

As speed increases, so does stopping distance. This is because the vehicle has more kinetic energy, which must be dissipated through braking, resulting in a longer braking distance.

## 5. What are some factors that can affect stopping distance?

Stopping distance can be affected by factors such as road conditions, vehicle weight, tire traction, and reaction time. It can also be affected by external factors such as weather conditions and the condition of the vehicle's brakes and tires.

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