Originally Posted by ericy (Post 9183720)

I find myself very short of breath when I attempt to bicycle in a vacuum :D.

Originally Posted by JTGraphics (Post 9183675)

:DThis is getting old real fast.

Originally Posted by Andy_K (Post 9178783)

Now it happens that while I don't ride a recumbent, I do have both an aerobelly and a degree in physics. I haven't used the physics degree lately and I'm lazy (which is why I haven't thought this through with any kind of rigor up to now), but this is the way I see it:

Let's say rider A weighs 220 and rider B weighs 110. The force due to gravity will vary depending on the slope, but it came be simplified as

F(g)(a) = 2x
F(g)(b) = x

where x is the weight of rider B times a factor to account for the incline. Now lets call the force from wind resistance y. For any given speed it will be about the same for both riders. So the net forces will be

F(net)(a) = 2x - y
F(net)(b) = x - y

Now for simplicity, let's consider the case where the gravitational force in for rider B is twice the force from wind resistance (x = 2y).

F(net)(a) = 4y - y = 3y
F(net)(b) = 2y - y = y

So at that speed (below terminal velocity), the rider with twice the weight will be experiencing three times the force, and therefore will be experiencing greater acceleration, even after you account for his greater weight.

Originally Posted by supramax (Post 9184034)

Have I said anything that you disagree with? If so, what?

Originally Posted by supramax (Post 9184071)

JTGraphics,

Your response is non sequitur.

Originally Posted by JTGraphics (Post 9184548)

Well when I said “This is getting old real fast” why did you think I was referring to you anyways?
I was referring to the thread going no where’s at this point.
So as I said this is going no place so no need to respond at least to me because I have nothing to say on this subject.

Originally Posted by Andy_K (Post 9184411)

Well, that depends. Are you simply espousing the principle that in a vacuum items fall at the same speed regardless of weight, or do you think that applies to cyclists not in a vacuum?

Originally Posted by Andy_K (Post 9184411)

Well, that depends. Are you simply espousing the principle that in a vacuum items fall at the same speed regardless of weight, or do you think that applies to cyclists not in a vacuum?

Originally Posted by supramax (Post 9184751)

Anyways, I'm going to bed. Bon soir.

Originally Posted by xenologer (Post 9185168)

I would say that it always applies since at the speeds that most cyclists travel at, differences in wind resistance between fat and skinny riders are negligable (ie the vacuum vs not effects aren't an important distinction).

Originally Posted by cooker (Post 9186039)

Hope you slept well. I'm curious what you're trying to accomplish is this thread. Since the OP is talking about downhill bicycling speed where clearly air resistance is a major limiting factor, does repeating some abstract and incomplete statement like "the speed of falling objects is independent of their weight [in a vaccuum]" contribute in any way to the answer to the question? You're a fairly new poster with some helpful contributions in other threads, and not a smart alec teenager - what got you into such a feisty, oppositional mood in this thread?

Originally Posted by supramax (Post 9186281)

I'm just trying to clarify something, because I can't understand why some people are having so much difficulty wrapping their brains around a simple fact that's irrefutably proven in a vacuum, but applies always.

Originally Posted by Andy_K (Post 9186323)

This is fairly bizarre. The majority of this thread has consisted of your "vacuum" principle being cited, somebody responding saying that wind resistance applies, followed by a counter response repeating the "vacuum" principle. I don't think anybody has disagreed with the principle. The only question is whether or not it directly applies to the original question without the need to consider air resistance.

Originally Posted by supramax (Post 9186281)

I'm just trying to clarify something, because I can't understand why some people are having so much difficulty wrapping their brains around a simple fact that's irrefutably proven in a vacuum, but applies always.

Originally Posted by Shimagnolo (Post 9186397)

I gave you the equations for a freefalling object in a fluid, but apparently you don't understand math.

Originally Posted by Andy_K (Post 9186323)

This is fairly bizarre.

Originally Posted by Febs (Post 9186448)

It's not bizarre at all. You're feeding a troll. That's what trolls do. DON'T FEED THE TROLLS.

Originally Posted by StupidTroll

"It's not my fault that 'cyclist' doesn't equate to 'having studied physics'.".

Originally Posted by Shimagnolo (Post 9179192)

Yes, you have given us proof of that.

Originally Posted by TwoShort (Post 9186483)

While he clearly hasn't studied physics, I've see no evidence he is a cyclist.

Originally Posted by supramax (Post 9186471)

Andy_ K,

It's NOT a vacuum example. It's proven in a vacuum (with the feather/hammer or whatever). The air resistance is negligable with a penny and a 5 lb barbell plate. Drop them (same time and height) and they'll reach the ground at the same time.