*gasp*
Horror of horrors! I finally began reading my copy of CoC today, and I stumbled across this myth of physics!
Page 29, Sidebar -- Cars and Other Vehicles:
No, no, no, no, no!
In any kind of interaction between two forces, energy must be conserved. If two cars (same make and model, for easy math) strike each other head-on while both are going exactly 60 miles-per-hour, and you add the speeds together, then you've got twice as much energy coming out of the collision as you have going into it. This can't happen. Why, oh why did WotC perpetuate this myth?!
If both cars are the same mass and traveling the same speed when they strike head-on, under ideal conditions, it's the exact same thing as each car hitting an immobile object (say, a really thick brick wall).
For a good explanation, go here.
Now, if the cars are traveling at different speeds, or are different masses, that's a completely different story.
However, to keep things simple in-game (I don't want to be doing kinematic equations and figuring out the elasticity of a collision at the table) I'd probably take the total speed and divide it by two (even though this is technically wrong) unless one car's speed or mass was orders of magnitude greater than the other (i.e. an 18-wheeler strikes a Yugo... I don't think the truck is gonna notice that much!).
Good grief... I always knew I was a geek, but I never thought I'd be ranting about the physics in a frickin' RPG source-book! Is there a clinic I can check myself into?!
Horror of horrors! I finally began reading my copy of CoC today, and I stumbled across this myth of physics!
Page 29, Sidebar -- Cars and Other Vehicles:
No, no, no, no, no!
In any kind of interaction between two forces, energy must be conserved. If two cars (same make and model, for easy math) strike each other head-on while both are going exactly 60 miles-per-hour, and you add the speeds together, then you've got twice as much energy coming out of the collision as you have going into it. This can't happen. Why, oh why did WotC perpetuate this myth?!
If both cars are the same mass and traveling the same speed when they strike head-on, under ideal conditions, it's the exact same thing as each car hitting an immobile object (say, a really thick brick wall).
For a good explanation, go here.
Now, if the cars are traveling at different speeds, or are different masses, that's a completely different story.
However, to keep things simple in-game (I don't want to be doing kinematic equations and figuring out the elasticity of a collision at the table) I'd probably take the total speed and divide it by two (even though this is technically wrong) unless one car's speed or mass was orders of magnitude greater than the other (i.e. an 18-wheeler strikes a Yugo... I don't think the truck is gonna notice that much!).
Good grief... I always knew I was a geek, but I never thought I'd be ranting about the physics in a frickin' RPG source-book! Is there a clinic I can check myself into?!
