The Physics of Phun

[JimmyMethod]

Today, I was driving back from work (an hour long process, so I have time to let my mind wander) and I was wondering why flying around corners is so much more fun than just shooting off the line.Then I realized why: It's the g's.Your body expirencing acceleration is what gets you that adrenaline rush, whether it's dropping the clutch in a V8, or going slideways through cones 15 feet apart. Doing the math in my head I had come to realize something: in order to get the same feeling of acceleration of a car (I used a 1.00g lateral to make the math easier) flinging itself around a 90+ degree corner just at the cusp of losing traction, you would have to have a car that could spring the 1/4 mile in less than 9 seconds... Here's the math =>1g = (about) 10m(eters)/s^21/4mile = (about) 400 meters =dv=10*td=5*t^2 => 80=t^2t = less than 9seconds...

(now don't start tearing this thread to pieces, saying how dumb I am because car's don't have linear acceleration. I understand that, but it made the math easier and it's not a BAD approximation)

in otherwords, it would have to accelerate at 22.5mph every second1 M(ile)/h = 4/9 m/s1g = 22.5 Miles/hr/s

Since the number of street legal cars that can do that is QUITE small (8.5, I believe is the legal limit, anyway)... I still don't understand the fascination with accelerating in a straight line. So few cars have the ablility to match a respectably handling car in terms of g-forces.

Anyway, that's my schick. Kinda interesting, at the very least.

...I'm glad I have a great handling car...

[dfw240_EE]

Very close, but you are ignoring gravity.

Consider my picture. The sum of 1 g of gravity and 1 g of lateral acceleration is squareroot(1g + 1g), or the square root of 2, which is 1.44 g.

Edit: Reading what you wrote abit deeper, what I stated is erroneous. The man in the theoretical 1 g drag car also experiences gravity, so 1g of linear acceleration would also effect 1.44g total.

I remember watching an American Le Mans series race. During some of the in car cams, they had a g-meter. Some of the top performance cars were touching 3 lateral g's. Again, factor in gravity, and you get a total experience of 3.16 g's.

[240DRFT]

you guys have too much time on your hands

[Florida240sx]

I'm lost.1g=1.44(with gravity)3g=3.16g(with gravity)Shouldn't it be 4.32

[rexhunta]

I'm lost.1g=1.44(with gravity)3g=3.16g(with gravity)Shouldn't it be 4.32

Umm, i got lost after i tried to read the title.

[JimmyMethod]

I'm lost.1g=1.44(with gravity)3g=3.16g(with gravity)Shouldn't it be 4.32

Acceleration is a vector, you have to add the squares of the horizontal components with the squares of the vertical components, then take the square root, to get total acceleration, i.e. use Pythgorean's threom. However, since we're always experiencing 1g downward, I ignored it.

It would NOT be 4.32 because :> (1g (down))^2+(3g(sideways))^2 = sqrt(10(g^2)) = 3.16gsTo understand it, it helps to draw a freebody diagram... :-pGood ol' High School Physics.

[ILikeMy240sx]

dude man... its summer lol enjoy your time off from Engineering and relax.. you will get plenty of that crap when you get to ME240 lol

[JimmyMethod]

dude man... its summer lol enjoy your time off from Engineering and relax.. you will get plenty of that crap when you get to ME240 lol

Hmm...prolly...

lol. Good old CoE.

[dfw240_EE]

dude man... its summer lol enjoy your time off from Engineering and relax.. you will get plenty of that crap when you get to ME240 lol

Never!What can I say, engineering is my life. Though this is mechanics, and I am electrical so I am not on as sure footing.

[InsanityInc]

Acceleration is a vector, you have to add the squares of the horizontal components with the squares of the vertical components, then take the square root, to get total acceleration, i.e. use Pythgorean's threom. However, since we're always experiencing 1g downward, I ignored it.

It would NOT be 4.32 because :> (1g (down))^2+(3g(sideways))^2 = sqrt(10(g^2)) = 3.16gsTo understand it, it helps to draw a freebody diagram... :-pGood ol' High School Physics.

But dive, squat and body roll would modify the gravity vector application angle relative to the angle of the accelerative force

[dfw240_EE]

No, gravity is always pointing down, and the acceleration vector will always point torward the inside of the turn. The only place where the vectors would not be orthogonal is on a banked turn.

[yoozef]

No, gravity is always pointing down, and the acceleration vector will always point torward the inside of the turn. The only place where the vectors would not be orthogonal is on a banked turn.

doesn't the acceleration vector point outwards? unless im confusing it with inertia of a body (in this case the driver on a turn), but i thought in this case it would be the same thing... im not too good with this stuff

[Florida240sx]

How about we close our study books and just open a beer.

[dft24ds]

Im down with the beer

[JimmyMethod]

doesn't the acceleration vector point outwards? unless im confusing it with inertia of a body (in this case the driver on a turn), but i thought in this case it would be the same thing... im not too good with this stuff

Inertia points straight, the force from the tires on the pavement points to the inside of the turn, gravity is always down, the normal force is always perpendicular to the surface (straight up, on a flat road).

[dfw240_EE]

doesn't the acceleration vector point outwards? unless im confusing it with inertia of a body (in this case the driver on a turn), but i thought in this case it would be the same thing... im not too good with this stuff

You are making a common error. A mass moving in a circle is constantly accelerating torwards the center of the circle. This acceleration is equal to the square of the velocity divided by the radius of the circle, or v^2/r. As your body wants to remain at rest, you feel an equal acceleration torwards the outside of the circle. There is absolutely no force pushing you to the outside of the circle. However, assuming there is a force pushing the mass to the outside is an accepted "cheat" in physics.

[240DRFT]

How about we close our study books and just open a beer.

sounds good but im only 17 so will u buy me some