Car accelerating behind me up to 40mph

In summary, the two questions discussed revolved around the impact of constant speed versus acceleration on a moving object and the behavior of a car accelerating behind another car. The conclusion is that in both scenarios, the impact and behavior of the objects will be the same regardless of the speed or acceleration.
  • #1
jimmy p
Gold Member
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Ok these are a couple of strange questions.

If you were traveling at a constant speed eg, 30mph and you hit someone, would it do more damage to them than if you were accelerating towards them up to 30mph when you hit them?

And this one, I know what the answer should be but I can't get my head round it. If I were driving at a constanst speed, say 40mph, and there was a car accelerating behind me up to 40mph, if I looked in my rearview mirror, would they be coming towards me, retreating from me, or staying in the same place? I think it is retreating from me...

Thanks

James
 
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  • #2
If you assume that in the impact the driving force on the wheels stops immediately on contact, or is negligible compared to the impact force, then it shouldn't make any difference whether the car is going at a constant speed or accelerating or slowing down.

On the second question, you are right. As long as it is going slower than you, it will recede. When it reaches your speed, it will stop receding and maintain a constant distance. In order to advance on you, it has to be going faster than you are.
 
  • #3
ceptimus said:
If you assume that in the impact the driving force on the wheels stops immediately on contact, or is negligible compared to the impact force, then it shouldn't make any difference whether the car is going at a constant speed or accelerating or slowing down.

On the second question, you are right. As long as it is going slower than you, it will recede. When it reaches your speed, it will stop receding and maintain a constant distance. In order to advance on you, it has to be going faster than you are.


So I still know something about physics! :biggrin: Thanks!
 

1. How does a car accelerate?

A car accelerates by increasing its speed or velocity. This is typically achieved by pressing down on the accelerator pedal, which controls the flow of fuel to the engine. The engine then converts the fuel into energy, which turns the wheels and propels the car forward.

2. What is considered a safe acceleration speed?

There is no specific speed that is considered universally safe for acceleration. It depends on various factors such as road conditions, traffic, and the performance capabilities of the vehicle. However, a gradual and controlled acceleration is generally recommended for safety.

3. How long does it take for a car to accelerate to 40mph?

The time it takes for a car to accelerate to 40mph varies depending on the make and model of the car. On average, it takes around 10 seconds for a typical sedan to reach 40mph.

4. Can accelerating too quickly damage a car?

Yes, accelerating too quickly can cause damage to a car's engine and transmission. It puts a strain on the components and can lead to premature wear and tear. It can also increase the risk of accidents if the driver loses control of the vehicle.

5. How can I safely accelerate behind another car?

When accelerating behind another car, it is important to maintain a safe following distance and to gradually increase your speed. Pay attention to the movements of the car in front of you and be prepared to slow down or stop if necessary. It is also important to use your turn signals to indicate your intentions to other drivers.

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