Feel free to ask me any question you wish.

whats this red mark on my sack

That was a hickey from gambit sucking too hard.


Next!

Why do you enjoy to follow bicyclists around and sniff their seats after they get off?

Does your dad know that I was the one who gave your mom herpes?

Yes.

Also, do not open mail with white powder in it for the next 6 months or so.

When will the chupacabras invade ee?

All lies, as most people know, I am too lazy to follow around bicyclists. As for sniffing their seats, it makes me feel happy inside.

In 77 days.

what is the air speed velocity of an unladen swallow?

how much does a pound weigh?

What is the specific gravity of a cheese and wine turd.

An African or European swallow?

A pound of feathers or a pound of bricks?

9.81 m/s^2

Actually
-9.81m/s^2

nub

if you give a moose a muffin, why does he also ask for a glass of milk?

So if you tossed a ball in the air where you are, and tossed a ball in the air in the exact opposite side of the earth. The balls will fall in relatively different directions in relation to each other. It being negative implies vector, but the fact that the 2 balls, fall in opposite directions implies it is not a vector. So the positive or negative value on gravity does not matter as it changes everywhere else relative to your current position.

if you give a moose a muffin, why does he also ask for a glass of milk?

Because he doesn't like to eat muffin's on their own.

No

the actual physics equation for the acceleration of gravit of earth is

-9.8m/s^2

because things fall down, losing altitude, hence the negative. Just because they fall toward a specific point, that actually implies a vector. The fall is constant and in a predictable direction, relative down. So yes, there is a vector.

that is not my opinion, it's physics



When will Donny post in this thread, and what will he say!

True gravity always does pull stuff towards the center of mass. But how can two balls be both falling in opposite directions and both have negative acceleration? As vector wise both directions cant be down.

Relative down, like I said.

All vectors are, by nature, relative. So for earth's gravity. It is a relative negative equation

Actually, you're wrong. it's 9.8m/s^2 TOWARDS the gravitational source, not away from it.

If it was -9.8m/s^2 that would indicate a body accelerating AWAY from a gravitational source.

It's a negative equation.

Say you drop something from 100 feet

If you use the equation in a positive sense, it will be gaining altitude? Incorrect.

Gravity brings things down. i.e. Lose altitude, I.e. Negative.

I understand what you 2 are saying. But in an equation, the relative acceleration of gravity is negative.

No it's not because of the frame of reference. Now if you're calculating escape velocities, I'd be inclined to agree with your assertion as acceleration due to gravity IS a "negative" in that frame of reference.

I guess it's how you use it. I always use it in a matter of where I'm calculating freefall altitude changes.

In that sense it's a negative integer. But if you are jus calculating velocity and not distance, I can see where the negative would not be needed

Bingo. It's all about the frame of reference. :)

In a freefall calculation you're basing your determination relative to your starting point. In that case, you're absolutely accelerating away from your initial altitude at -9.8m/s^2

"With respect to what" was a question my College Physics professor always asked if you gave an answer.

sneaky chupacabra! qwit it wit ur maths!

Had no Idea I'd be revisiting Physics class coming here...

""With respect to what" was a question my College Physics professor always asked if you gave an answer." - I used to get that lol

K4F

Will Gambit ever make hot love to me again?

Debating a turd! Awesome!!

Only if your eyes are closed and you are leaning over to pick something up.

debating physics of a turd... even better

If you put a airplane on a treadmill

would it take off?

if you put a turd on a treadmill would be better fordy

No, the airplane has to be moving forward in the air for the wing dynamics to create lift (pressure lower above wings then under.)

No matter how fast plane is moving in relation to ground, it needs to be moving in relation to the air.

what about a harrier?

Harriers move the air and create lift similar to a helicopter for a vertical takeoff, so it can go straight up no problem and once it is off the treadmill it can move forwards angling the engines until it reaches a speed where the winga create their own lift.

Actually. A plane on a treadmill would take off

it was a trick question!

Well assuming the treadmill was going backwards as fast as the plane was going forwards, so the plane was not moving. Then it wouldn't take off :P

Wheels have nothing to do with the movement of the airplane. Since the wheels are just there for friction purposes, and the propulsion is thrust based, and not rotational, once the plane started moving the treadmill would be irrelavent.

Trust me :)

I thought you meant that a treadmill as a item which will stop the forward motion of an object.

If a treadmill was going fast enough backwards the friction in the wheel rotation would slow down the plane enough to stop it from going forwards as well.

incorrect

the treadmill could never overcome the thrust of a jet airplane. unless the wheels failed, it would take off

p.s. google this question, you will fine insanely heated debates across multiple forums. they are all entertaining reads, but physics are on the side of taking off

and the mythbusters did a bit on it lol

I am considering a theoretical treadmill, since planes cant really go on a normal treadmill anyway. If the treadmill belt was going backwards fast enough, the friction in the wheels would provide a force going in the negative direction (Although the wheels will be turning ridiculously fast in order to get that magnitude of friction. Entirely possible with a treadmill that we can invent), and the force pulling it back will cancel out the force of the engines pushing the plane forwards.

Basically what I am saying, is that if the plane is not moving forwards in relation to the air, the plane will not fly.
If the treadmill doesn't move back fast enough to stop a plane from moving in relation to the air, the plane will eventually take off.

I believe my statement above is true, but it works with the way I thought the treadmill was supposed to work. With the way your treadmill works the plane will indeed take off.

my point is, the treadmill is muted by the method of thrust of the plane. it really does not matter how fast the treadmill is going, it could be going 1 billion miles an hour, with the thrust, the wheels would just spin faster, and it would still move forward. its a common mistake because most people associate wheels with propulsion because of cars.

it would be like pulling yourself along a treadmill on roller skates. no matter how fast the treadmill is going, there is a force unrelated to the wheels acting as propulsion, therefore propelling you forward no matter the speed of the treadmill

Almost correct mrford, if there was no friction. But there is friction, and even a small portion of the friction will cause the wheels give a negative force back. For example in a car if you are going say 150 km/h, then turn off your engine, or put it into neutral, the car lurches as if you slammed on the breaks, and slows down fairly fast. If there was enough friction pushing the wheels back, some of it, even a small portion of it is transfered to the plane.

And your rollerskate example, I would love to see someone try that on a super fast treadmill :P The force pushing you forwards may be independent of the speed of the treadmill, but the treadmill force pushing you backwards is still a force that needs to be compensated for if you wish to move forwards. If the force pushing you back is so high, that you can't move forwards, all you can do is just enough to compensate for it, then you don't move at all.

Do you not agree that a treadmill going against the direction you are trying to go will cause friction that will "push" you backwards?

I agree. But the force of the engine will easily overcome the only opposing force, which is friction

all of the examples you have given, I.e. The car, you remove the force opposing the friction and sure, it will have an effect

what you are apparently stating is you think that the 4 engines on a 747 could not overcome the friction of the wheel berrings? Come on. Think about it. Wheel friction is a force so minimal when compared to the thrust of the engines, that the only possible outcome, based on the physics, is forward motion and the inevitable takeoff if the plane. Theoretical treadmill or not, without some physical force other than the minimal friction is needed to prevent the plane from taking off

as insightful as this was, I still liked the idea 'if you put a turd on a treadmill'


Say we put a new motor on the treadmill so it can reach speeds of 100 km/h. There is a wall 3 metres behind the treadmill.
If I back out a log onto the treadmill while it was on, how big would the splatter be on the wall?

<3

What is the mass and relative density of said log?

It varies from person to person and movement to movement, so to speak. We've all had ones that sink without trace, wondering if we imagined doing one. Alternatively there are those that float and won't be removed regardless of number of flushes. (These ones are known as 'Mr Bond's: "We meet again, Mr Bond.")

On average, close to the density of water, I'd say.

The actual density of water is one gram per millilitre at 4 degrees C. (not from approved source)

I don't care if you use that in your equation, the runnier the better the splatter.

I'd also like to think I would have prepared for the moment and could muster a good half kilogram at least.

i dunno what you have k4f but if i put my truck in nuetral going 70 miles an hour, it doesn't lurch at all. it simply loses acceleration

Aye mrford, agreed that the wheel bearing force is minimal. But all the treadmill has to do is cause enough force in the opposite direction to stop the plan from reaching takeoff speed. If it isn't moving fast enough it cant take off.

So if the treadmill is moving backwards fast enough (and yes I agree it would have to be a stupid fast speed for that to happen, like 10,000 km/h) it would slow the plane down enough so between air friction, and the treadmill wheel bearing friction it is possible to stop a plane from taking off.

Also depends on the type of planes, some planes, especially smaller ones, need 90% of their power right away to begin taking off successfully, I can easily see a Cessna not being able to take off as wheel friction plays a far bigger part. Where as a 747 I agree, since it has so much overkill powerwise, it might be able to take off anyway, but I disagree that if the treadmill was moving 1bil km/h it would be able to. If for only the reason the plane wouldn't to go in a straight line, since it is likely the tires will melt, or at least have no friction in relation to the treadmill.

Now that I think about it, if the treadmill was moving fast enough, the bearing friction would cause the bearings to heat up, and when metal heats up it expands, bearings fit snugly together so even a moderate increase in heat will expand the bearings, then the friction will jump up exponentially as the wheels will be unable to move. (Again this is only for speeds of several thousand km/h +)