- #1

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In summary, two cars with the same mass will experience the same impact when colliding with each other at 30 mph, which is equivalent to hitting an immovable wall at 15 mph. If the cars are moving in opposite directions, the impact is equivalent to hitting the wall at 30 mph. The extent of damage depends on the crumple characteristics of the car and the kinetic energy lost in the collision. Ultimately, the speed at which a car needs to hit a wall in order to have the same impact as a collision with another car depends on the wall's material and the time it takes for the car to come to a complete stop.

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- #2

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It depends what the wall is made of.

- #3

Halc

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Two cars with a relative speed of 30 mph (I assume you mean mph and not miles) will each receive about the same impact (same short-duration change in velocity, same damage) as hitting a stationary immovable wall at 15 mph.

If on the other hand the cars are each moving at 30 mph in opposite directions (a relative speed of 60 mph), then they will each receive about the same impact as hitting the wall at 30 mph.

- #4

nirgro

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sorry not sure i got what you say

2 cars hit each other at the speed of 30 each one of them.its like one car hits the wall at 15??

isnt it like a car hit a wall at 60?

2 cars hit each other at the speed of 30 each one of them.its like one car hits the wall at 15??

isnt it like a car hit a wall at 60?

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- #5

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You might be losing this bet!nirgro said:sorry not sure i got what u say

2 cars hit each other at the speed of 30 each one of them.its like one car hits the wall at 15??

isnt it like a car hit a wall at 60?

- #6

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nirgro said:isnt it like a car hit a wall at 60?

PeroK said:It depends what the wall is made of.

It also depends on the crumple characteristics of the car. Your question is way too vague to have a solid answer.

- #7

nirgro

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why?

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If the wall is unbreakable and immovable, then hitting it at 30mph is the same as two cars hitting each other if both are doing 30mph. The impact on the car is the same: it stops dead from 30mph to zero with no forward motion.nirgro said:why?

- #9

etotheipi

If two cars, each with ##v_0 = 15\text{mph}## (i.e. approach speed ##2v_0 = 30\text{mph}##) hit each other, then each is still apportioned ##\frac{1}{2}m{v_0}^2## worth of deformation. This assuming symmetry, of course.

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Why WHAT? Which statement are you questioning?nirgro said:why?

- #11

nirgro

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so i lost the bet but still nice to know

thanks.

- #12

Mister T

Science Advisor

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Usually in a question like this we assume the time taken is the same in both cases, or at least about the same, so that it makes no difference. The damage is the same in both cases.

The outcome of a collision between two cars is affected by several factors, including the speed and mass of the cars, the angle of impact, and the presence of safety features such as airbags and seat belts. The type of collision, whether it is head-on, rear-end, or side impact, also plays a significant role in determining the outcome.

In a collision between two cars, the force of impact is shared between the two vehicles, as they both exert a force on each other. In contrast, when a car hits a wall, the force of impact is absorbed entirely by the car, resulting in a higher force and potentially more damage.

While it is possible to make predictions based on the factors mentioned above, the outcome of a collision is ultimately unpredictable. The behavior of the vehicles and the forces involved can vary greatly depending on the specific circumstances of the collision.

Safety features such as airbags and seat belts are designed to reduce the impact forces on the occupants of a vehicle during a collision. They can significantly decrease the likelihood of serious injuries or fatalities in a collision.

While it is not possible to completely eliminate the damage in a collision, there are steps that can be taken to minimize it. These include driving at safe speeds, maintaining a safe distance from other vehicles, and ensuring that safety features are in good working condition.

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