Official Physics Thread



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Ok, for a start...

It id often a common conversation on the mountain, "Why are you faster than me" or "You are faster because you are heavier." This is often said on a nearly flat access trail.

Majority of the time in my case, this appears to be true.

But of course we know that 2 objects of different mass when acted upon by gravity will still have the same acceleration, and will "fall" (or in our case, fall on a slant) at the same speed.

Other factors I have considered include:

>Drag

>Friction (ski wax, ski surface area, edging)

>Line (faster snow, inside lane)

>inertia(!?)

I do not know if this is the right word for my train of thought, but... Wouldn't for example, a very heavy object on skis be able to penetrate or pierce through the snow easier than a light ski would?

Wouldn't a heavy skier have more mass behind them be be able to smash through small bumps on the snow easier than a light skier could, due to the heavy skier having lost of mass behind their movement and would need more to slow them down?

Any response would be cool.
 
Ya it's probably because of what you said. It's like a small boat trying to keep up with a large one on the ocean, the large one will be faster even if they are initially going the same speed because it is not affected by the waves as much.
 
fiziks is fake and u all are goin to hell. gravity is the devil pullin us 2 hell and thats why jesus could walk on water because god was pulling him to heavin
 
I was thinking about adding physics as a dual major to mechanical engineering, but the start of this semester has me rethinking that. FUUUUUCK electricity and magnetism, class average on the first test was a 35%, fucking electric fields and shit.
 
Okay, so i hve this challenge for myself to apply a gyroscope to my monopod in the simplest way because i think the MovI is to complicaded.Ive been thinking on attaching a small bikewheel to it somhow, but it's still on the thinking stage.

I think it's a simple solution to it, but i just have to give it some more time and drawing i guess:)

 
Wat.

Assume frictionless -> a = g

Assume start from rest -> v = .5*g*t*t

Momentum -> p = m*v

Plug in -> p :: g
 
Mass and weight are different though. So p=mv doesn't imply g is needed, right? Gravity is the force that causes weight, so to speak. An object floating around in space under very low (zero) gravity still has m and v, so it has p too.
 
Every instance of momentum isn't derived from gravitational acceleration (IE: your example, or simply a person walking on a level street). But, in the example he was referring to the momentum is a result of gravitational acceleration
 
That's a cesspool of fruitless discussion and heated debate.

Mention that at a neuroscientist convention and by the end of the evening camps will have been formed, bunkers built from chairs and tables and the luxury canapés will be used as cruise-missiles.
 
Ok, this is getting sad.

Mass, Frictional force, and angle of slope are the factors that will influence speed. Mass is the total weight of the skier times 9,81 N for conversion. Mass also carries momentum. A light person will slow down faster because the energy built up per mass unit is weaker. M=mV M is momentum, m is mass and v is velocity.

Now the slope angle remains constant for both skiers.

Frictional force is were you equipment comes into play. the force of friction depends on gravitation force of your mass, surface area of the skis, gliding agent, slope angle and snow humidity. Think of this as an inclined planes problem.

Technique can be a factor in a bumpy terrain. A skier that absorbs the bumps and pushes on the downside will conserve momentum better than a person hitting moguls without control.

So to go faster on flat you have to be heavy, have good waxed skis and have a ski that wider.
 
I want to make a simpler version of the movi, which is a advanced camera stabilazor who is powered by a couple of gyroscopes. I think i can moke one that works with a single wheel. I just have to come up with a simple solution.

 
I am assuming that D means position? This is still not exactly correct.

Just say that v = dx/dt and a = dv/dt and then you don't need worry about those silly formulas!
 
no. it doesn't. That's why I never rely on formulas like that. You forget them. To get d you would need to know the initial position and velocity, and for Δd you would need the initial velocity.
 
I like the bungee jumping question. If you have a bungee jumper, and someone free-falling beside them, who will accelerate faster?
 
I don't need to look it up. I suppose it could, depending on what reference frame you use, but in a lab-fixed frame that formula would not work. Seriously, just use the formula I posted above and it's easy to see this...
 
I am talking about the freefall, before the bungee catches the person. If you want you can replace the bungee with an inextensible chain. and the people with bowling balls just to be less mean. before the chain catches the ball, will the two balls have the same acceleration?
 
well I still wasn't really embarrassing myself. I mean you were technically incorrect... I don't know what level of physics you are at, judging by the notation you use it seems like freshman/sophomore?

It sounds dumb, but you can often tell what level of physics someone is at by what symbols they use haha.
 
well my equation does not require the initial velocity to be zero, but now that's just splitting hairs.

 
Well if there is no other force acting on either person besides the force of gravity then they should be accelerating at the same rate, I'm guessing there's some sort of catch I'm missing though.
 
yo might be on the right track when you thought about the tension in the bungee. I was just clarifying that we are not talking about after the chain/bungee has started to "catch" the person. In other words the rope is still hanging in a U shape.
 
anyways this was actually done in a Veritasium video. So i'll just post it. Try and think about it before you look at the solution. I initially got it wrong, but then I thought about it again and figured it out and was right. Man that seems so long ago now...

 
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