Game Maker's Garage Forum

Game Maker's Garage => Trash Talk => Topic started by: Silverwind on August 24, 2010, 04:24:49 PM

Title: Determining the force of impact of two cars...
Post by: Silverwind on August 24, 2010, 04:24:49 PM
Me and a friend are hot in debate over the force of impact resulting from two objects colliding at different speeds.

Supposing a blue car travelling at 100mph collides with a red car travelling at 50mph, what are the forces of impact for both cars? Both of us agree that the force of impact would be 50mph if both cars were traveling at 50mph, but what about 100 and 75?
Title: Re: Determining the force of impact of two cars...
Post by: Gan on August 24, 2010, 06:11:29 PM
25 in the blue car's direction.


-Gan
Title: Re: Determining the force of impact of two cars...
Post by: Silverwind on August 24, 2010, 06:28:29 PM
Whoops, I meant to say 100 against 50, not 100 against 75. That answers my question though, and I win the debate! ;D
Title: Re: Determining the force of impact of two cars...
Post by: EqwanoX on August 24, 2010, 08:33:11 PM
what? it would be 150mph for each car
Title: Re: Determining the force of impact of two cars...
Post by: Gan on August 24, 2010, 08:42:37 PM
 ???
That's a crazy number, how'd you get that?


-Gan
Title: Re: Determining the force of impact of two cars...
Post by: Silverwind on August 25, 2010, 12:06:48 PM
But if the equation is:
Code: [Select]
blueCarImpactForce = blueCarSpeed - redCarSpeed
redCarImpactForce = redCarSpeed - blueCarSpeed
Then the force of impact for the red car seems to come out as -50mph! :-/

EDIT:

Wait a minute... that can't be the equation, as otherwise two cars traveling at the same speed would result in the impact force of 0mph, as if they hadn't collided at all!
Title: Re: Determining the force of impact of two cars...
Post by: Gan on August 25, 2010, 12:40:36 PM
Speed is important, but just as important is direction.
Speed and direction together is called Velocity.

If car A is going 50mph North and car B is going 50mph South and they collide their impact will have an outcome of 0mph. Of course their cars will be flattened, crunched, and have dead passengers...

When trying to figure this out keep direction in mind.


-Gan
P.S. I can give you the real equation though it involves vectors. A vector is a magnitude and direction. Such as 50mph North. It uses trigonometry to find the correct speed and direction outcome of two colliding objects.
Title: Re: Determining the force of impact of two cars...
Post by: Silverwind on August 25, 2010, 12:53:44 PM
Quote
If car A is going 50mph North and car B is going 50mph South and they collide their impact will have an outcome of 0mph.
But that can't be right, because if a car hits a stationary object at 0mhp (in other words, it doesn't hit a stationary object) it wouldn't receive any damage, yet two cars colliding at 50mph certainly would (assuming the cars are traveling in polar opposite directions in a vacuum).

This sum is giving me a headache...
Title: Re: Determining the force of impact of two cars...
Post by: Gan on August 25, 2010, 02:10:44 PM
Take your hands and clap them. Your hands are at a certain speed while traveling towards each other. When they collide clasp your hands with your fingers.
As you'll notice your hands go from a certain speed to 0.
That's exactly how colliding cars act if they crash head on into each other.


-Gan
Title: Re: Determining the force of impact of two cars...
Post by: Jinxycat on August 25, 2010, 02:50:02 PM
Silverwind, this is insane! Not only are you driving me crazy by talking nonstop about it but now your driving other people crazy.

I don't think anyone will ever be able to work it out. Test your mind on this instead: Why is a raven like a writing desk?
Title: Re: Determining the force of impact of two cars...
Post by: Silverwind on August 25, 2010, 02:52:44 PM
Quote
Take your hands and clap them. Your hands are at a certain speed while traveling towards each other. When they collide clasp your hands with your fingers.
As you'll notice your hands go from a certain speed to 0.
That's exactly how colliding cars act if they crash head on into each other.


-Gan
LOL! ;D Funniest answer ever, yet I'm still confused. How can the damage resulting from two cars colliding with an impact force of 0mph match the damage resulting from a single car colliding with a stationary object at 50mph?

Quote
Silverwind, this is insane! Not only are you driving me crazy by talking nonstop about it but now your driving other people crazy.

I don't think anyone will ever be able to work it out. Test your mind on this instead: Why is a raven like a writing desk?
They're not!
Title: Re: Determining the force of impact of two cars...
Post by: Connors on August 25, 2010, 04:56:01 PM
Silverwind all he said is that after the cars that are both doing 50mph hit and are mangled their total speed will be 0. They will stop moving[/i][/u].
I haven't heard the term impact force but I assume that's how much force the car receives when it first hits and before it changes direction or stops?

PS:
Quote
They're not!
I bet theres a way they are.
Title: Re: Determining the force of impact of two cars...
Post by: Gan on August 25, 2010, 06:28:51 PM
If the cars crunch into each other and become one then their combined speed will be 0mph. If they don't crunch into each other and just bounce into each other then they will fly in the opposite direction at a speed a little less due to friction.


-Gan
Title: Re: Determining the force of impact of two cars...
Post by: GMG Mike on August 25, 2010, 06:52:49 PM
When the cars crunch into each other all of the momentum is used up crushing the steel. The cars will go from 50 mph to 0 mph instantly but that momentum (energy) doesn't just go away, it has to be used up somehow. All of the steel is crushed up, this also releases some heat (have you ever bent some metal back and forth several times to break it, then felt the ends and it was hot?)
Title: Re: Determining the force of impact of two cars...
Post by: Connors on August 25, 2010, 07:37:12 PM
Exactly what I was getting at! and hf one was going faster then the wrecked cars would skid in the direction of the faster car.
Title: Re: Determining the force of impact of two cars...
Post by: Jinxycat on August 26, 2010, 08:00:08 AM
Quote
I bet theres a way they are.

Yup, Lewis Carroll himself answered it: "Because they're never put with the wrong end in front and because they both produce a few notes, although they are very flat". Hehe.
Title: Re: Determining the force of impact of two cars...
Post by: Silverwind on August 26, 2010, 12:55:09 PM
Hang on, I did a terrible job at wording the question and now there's a misconception over what it is I'm actually asking! ;D

I wasn't asking what speed the cars would be traveling at upon colliding with each other, I was asking how much damage they'd sustain. I wanted to know if the individual damage received by two cars colliding at 50mph would be double to the amount a single car would receive upon colliding with a wall at 100mph (assuming that the wall had an absorbance factor of 0, that both cars were traveling in polar opposite directions and that both collisions occurred in a vacuum)

It was put to me that the amount of individual damage received in the two car collision would be double to that of the car colliding with a wall at the same speed (due to the doubled speed of approach) but I disagreed on account of there only being 100mph worth of energy in the two car collision, which wouldn't accommodate for 200mph worth of damage. The misconception was due to me using the term "force of impact", hehe...

Anyways, case solved. Old Silver was right! ;D
Title: Re: Determining the force of impact of two cars...
Post by: GMG Mike on August 26, 2010, 08:43:44 PM
If a car hits a wall at 50 MPH, it sustains 50 MPH "worth" of damage. The entire force of the car's momentum is used up crushing the front end of the car.

If two cars hit each other, perfectly head to head, and each car was going 50 MPH, you have 100 MPH worth of total damage but it's spread between two cars, so each car would receive about 50 MPH worth of damage.

Doubling the speed that a car hits a wall does not double the damage (at least if you are measuring the damage monetarily). For example, 1 MPH vs 2 MPH are probably about the same - you would just scratch the paint a bit.
Title: Re: Determining the force of impact of two cars...
Post by: Silverwind on August 27, 2010, 04:33:30 AM
Quote
If two cars hit each other, perfectly head to head, and each car was going 50 MPH, you have 100 MPH worth of total damage but it's spread between two cars, so each car would receive about 50 MPH worth of damage.
Yeah, exactly. That's what I thought. :)

Quote
Doubling the speed that a car hits a wall does not double the damage (at least if you are measuring the damage monetarily). For example, 1 MPH vs 2 MPH are probably about the same - you would just scratch the paint a bit.
Well, the difference might not be humanly noticeable, but twice the amount of energy has gone into damaging the car(s). That's actually how the debate started, and then we tried to determine the amount of damage each individual car would receive upon colliding at different speeds (as in, how fast a car would need to be traveling upon collision with a wall in order to receive an equivalent amount of damage to that of the two cars).

The answer is: two cars colliding with each other at 100mph and 50mph will respectively receive an equivalent amount of damage to that of a single car colliding with a wall at 50mph and 100mph. I think...
Title: Re: Determining the force of impact of two cars...
Post by: Connors on August 28, 2010, 07:45:46 PM
(takes a deep breath) OK OK If what they just said is right that means that 2 cars going at 50MPH and 100MPH hit each other head on they both receive about 75mph "worth" of damage because that's half the total.



PS: This whole thing looks pretty familiar...
Title: Re: Determining the force of impact of two cars...
Post by: Silverwind on August 29, 2010, 03:48:40 AM
Not exactly, because both cars will receive different amounts of damage. The slower car's damage will be equivalent to that of a single car hitting a wall at 100mph, while the faster car's damage will be equivalent to that of a car hitting a wall at 50mph.
Title: Re: Determining the force of impact of two cars...
Post by: Silverwind on September 02, 2010, 05:12:28 PM
Ack, I got the priest involved and now I'm totally confused again! (http://img251.imageshack.us/img251/3595/wacko.gif)