# Kinematics Crash Simulation Question

• tobya93
In summary, Arka420 says that the equation d = ((Vi + V)/2) * t is not very useful, and that it is also very seldom you can use average speed. He also said that the equation V^2 = Vi^2 + 2ad is useful, and that for time they used V = Vi + at.
tobya93
1. In a crash simulation, a car traveling at x m/s can stop at a distance d m with a maximum deceleration. If the car is traveling at 2x m/s:

A. Stopping time is doubled
B. Stopping distance is doubled
D. Both A and C

Ok, so I thought this was a relatively easy question. However, I managed to butcher it. My problem is, I do not understand which equation to use. To find if the distance doubled or quadrupled I used the equation: d = ((Vi + V)/2) * t. Since the car will be stopping the V will be zero and you simply get d = (Vi/2) * t. If the velocity is doubled, distance is doubled. However, the book used the equation V^2 = Vi^2 + 2ad. Thereby getting, stopping distance quadrupled.

Also for time they used V = Vi + at.

Once again, I am lost to know which equation to use. Since both seemed to work..

Hello Toby, and welcome to PF.
Pity you didn't use the template. Any good reason for that ? Because now I don't know what material (equations) you have available to tackle this.
Also, variable names, given/known data are a bit messy now.

Your d = ((Vi + V)/2) * t is not very useful, since you don't know t (or did you assume t is the same for x m/s and 2x m/s ?). It is also very seldom you can use average speed, so better stay away from this equation if possible (by happenstance it is in fact correct here)

1.) Are you familiar with d = x * t + 1/2 * a * t2 for motion under constant acceleration(/deceleration) ?
Usually written as ## S = v_0\, t + {1\over 2}\, at^2##

2.)
for time they used V = Vi + at
gives the impression you don't recognize this. Is that really unfamiliar ?

3.) Do you recognize
? In another way: do you know about kinetic energy and the work done by a braking force that acts over a distance d ?

I get a notification "Arka420 has just replied ..." time stamp 20140623 15:22:15 +0000 but don't get to see it posted. Some good spirit got crossed at the considerable giveaway therein? But an identical notification must have been mailed to Toby at he same instant, isn't it?

If spiritual activity was indeed called for, leave something less telepathic for mere earthlings, please. Is Toby being helped meaningfully now (or rather, since originally posting, two weeks ago)?

## 1. What is kinematics crash simulation?

Kinematics crash simulation is a method used to predict and analyze the movement and behavior of objects during a crash or impact. It involves using mathematical equations and computer simulations to recreate real-world scenarios and understand the physical forces involved in a crash.

## 2. Why is kinematics crash simulation important?

Kinematics crash simulation is important because it allows us to understand the dynamics of a crash and evaluate the safety of a vehicle or object. It also helps in designing and improving safety features and reducing the risk of injury or damage in the event of a crash.

## 3. What data is needed for kinematics crash simulation?

Kinematics crash simulation requires data such as the mass, dimensions, and material properties of the objects involved in the crash, as well as the speed, direction, and angle of impact. It may also require information about the environment and any external forces, such as friction or gravity.

## 4. How accurate is kinematics crash simulation?

The accuracy of kinematics crash simulation depends on the quality of the data input and the complexity of the simulation. With accurate data and advanced simulation techniques, it can provide a realistic representation of a crash scenario. However, it is always important to validate the results with real-world tests.

## 5. Who uses kinematics crash simulation?

Kinematics crash simulation is primarily used by automotive and transportation industries, as well as research institutions and government agencies. It is also used in other fields such as aerospace, sports, and military to analyze the impact and safety of objects or equipment.

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