Weightlifting mathematically

[callan]

weight = force
you weigh nothing freefalling out of a plane, your mass is the same

weight = force of gravity on an object

 

[0ni]

Good old Wikipedia. This is where I reference the wiki page for 'Weight' which will inevitably state something like 'weight is the product of mass and gravitational force'. Which you have agreed is constant for all considerations.

Ah well, I'm starting to realise that your conversation ain't worth staying awake for tonight. Hilarious some days, innane the next.

Anyone else want to roll with this? I'm going to sleep.

I have supplied multiple sources for my information and you have supplied none.
You mention that the wikipedia article on weight describes weight as a dependant on gravitational force. This is true but is not an argument against what I am saying, rather for. G-forces increase or decrease when acceleration increases or decreases. Therefore weight increases or decreases

 

[Bella]

 

[0ni]

What!?
Weight = the force of GRAVITY
Mass = the amount of matter an object contains

You freefall BECAUSE of the force of gravity acting on you therefore you have weight, if you weighed nothing then you wouldn't be falling in the first place.

When you reach terminal velocity the force acted on you is 0. So your weight is 0. If there was a force pushing you down you would be accelerating. You weigh something when you're on the ground because the ground is pushing up on you against gravity - this does not happen when you are freefalling

I have to go to sleep now so will most likely not answer until tomorrow afternoon

 

[Darkoz]

g-force - Wikipedia, the free encyclopedia

"The term g-force is technically incorrect as it is a measure of acceleration, not force. While acceleration is a vector quantity, g-forces are often expressed as a scalar, with positive g-forces pointing upward (indicating upward acceleration), and negative g-forces pointing downward. Thus, a g-force is a vector acceleration.

G-forces, when multiplied by a mass upon which they act, are associated with a certain type of mechanical force in the correct sense of the term force, and this force produces compressive stress and tensile stress. Such forces result in the operational sensation of weight, but the equation carries a sign change due to the definition of positive weight in the direction doward, so the direction of weight-force is opposite to the direction of g-force acceleration:
Weight = -mass x (g-force acceleration)"

"The experience of no g-force (zero-g), however it is produced, is synonymous with weightlessness."
Less g-force (net force with or against gravity) = less weight

Seriously Oni, how many negative Gs do you think you're pulling when you lift a weight, enough to make the bar weightless?
Come on please.

 

[0ni]

weight = force of gravity on an object

The force of gravity (g-force) increases or decreases dependant on acceleration
Think going round a corner really fast, g-forces increase

 

[0ni]

Seriously Oni, how many negative Gs do you think you're pulling when you lift a weight, enough to make the bar weightless?
Come on please.

I did not say the bar would be weightless, just that it would weigh less
There is a point, a split second in the olympic lifts when the bar is weightless though - when you're dipping down and the bar stops accelerating up and starts accelerating down

 

[callan]

The force of gravity (g-force) increases or decreases dependant on acceleration
Think going round a corner really fast, g-forces increase

gravity pulls down..... not sideways
that is just a resistance to change direction, inertia

 

[Darkoz]

When you reach terminal velocity the force acted on you is 0. So your weight is 0. If there was a force pushing you down you would be accelerating. You weigh something when you're on the ground because the ground is pushing up on you against gravity - this does not happen when you are freefalling

I have to go to sleep now so will most likely not answer until tomorrow afternoon

Not quite, in freefall you're weight is still the same but you have ONLY the force of gravity acting upon you however, you don't FEEL your weight because you don't have the additional force of the ground acting against you therefore you have a SENSE of weightlessness.

 

[callan]

Not quite, in freefall you're weight is still the same but you have ONLY the force of gravity acting upon you however, you don't FEEL your weight because you don't have the additional force of the ground acting against you therefore you have a SENSE of weightlessness.

drag.... u still hit air...

 

[0ni]

I've decided that I have said all that I can say on the subject but will just add that the equation to work out weight (weight = mass* force of gravity) does not use gravity as a constant. Gravity is a constant but the FORCE of gravity is completely relative. When you're freefalling (assuming no air drag, you're in a plane freefalling or w/e) gravity could stop completely and you would be weightless still. If you're moving at terminal velocity, the force of gravity cannot act against you - it's like going around on a roundabout as a kid, you keep pushing with your leg but eventually you get so fast you cannot make it go round faster - the force outputted by your leg (gravity) is a constant but the force acted by your leg against the floor/roundabout (force of gravity) is diminished.

Feel free to PM me about it but I cba with these 10 page arguments any more

 

[Goosey]

No one has mentioned friction.
It's everywhere externally and internally and without it we would not be able to stop.

 

[Goosey]

Feel free to PM me about it but I cba with these 10 page arguments any more

Classic!

Avalookathis 0ni, I think you need to learn how to have a discussion, either that or being hit on the head lessons.

[ame=http://www.youtube.com/watch?v=kQFKtI6gn9Y&feature=youtube_gdata_player]Argument Clinic - YouTube[/ame]

 

[Darkoz]

I've decided that I have said all that I can say on the subject but will just add that the equation to work out weight (weight = mass* force of gravity) does not use gravity as a constant. Gravity is a constant but the FORCE of gravity is completely relative. When you're freefalling (assuming no air drag, you're in a plane freefalling or w/e) gravity could stop completely and you would be weightless still. If you're moving at terminal velocity, the force of gravity cannot act against you - it's like going around on a roundabout as a kid, you keep pushing with your leg but eventually you get so fast you cannot make it go round faster - the force outputted by your leg (gravity) is a constant but the force acted by your leg against the floor/roundabout (force of gravity) is diminished.

Feel free to PM me about it but I cba with these 10 page arguments any more

You make no sense Oni and WE cbf arguing with you anymore.
You MAY know what you mean in your head but your explanations are rubbish.

 

[0ni]

I literally have no idea how I can explain it more clearly to you than weight = force
How the fuck is that difficult to understand? Are you deliberately trying to rustle my jimmies?

 

[chocchillimango]

I've decided that I have said all that I can say on the subject but will just add that the equation to work out weight (weight = mass* force of gravity) does not use gravity as a constant. Gravity is a constant but the FORCE of gravity is completely relative. When you're freefalling (assuming no air drag, you're in a plane freefalling or w/e) gravity could stop completely and you would be weightless still. If you're moving at terminal velocity, the force of gravity cannot act against you - it's like going around on a roundabout as a kid, you keep pushing with your leg but eventually you get so fast you cannot make it go round faster - the force outputted by your leg (gravity) is a constant but the force acted by your leg against the floor/roundabout (force of gravity) is diminished.

Feel free to PM me about it but I cba with these 10 page arguments any more

Oni, you are unfortunately mistaken, my friend.

*physicist clears her throat*

Force = mass x acceleration.

"force of gravity" is a rubbish term. What you really mean is that

Weight is a force.
What we love to call "g" is actually the gravitational acceleration on our good earth.
Towit ... Weight (a force) = mass x gravitational acceleration

The acceleration due to gravity,g, as measured on earth is essentially constant to within a number of decimal places.
As such, we generally treat it as a constant.

Oni, I'm afraid the guys are right. Your explanation is both incorrect and unclear.

hope this helps

PS you have confused the matter by talking about spinning on a roundabout. This is not longer a matter simply of linear motion, but introduces the concept of angular momentum.

 

[0ni]

Oni, you are unfortunately mistaken, my friend.

*physicist clears her throat*

Force = mass x acceleration.

"force of gravity" is a rubbish term. What you really mean is that

Weight is a force.
What we love to call "g" is actually the gravitational acceleration on our good earth.
Towit ... Weight (a force) = mass x gravitational acceleration

The acceleration due to gravity,g, as measured on earth is essentially constant to within a number of decimal places.
As such, we generally treat it as a constant.

Oni, I'm afraid the guys are right. Your explanation is both incorrect and unclear.

hope this helps

PS you have confused the matter by talking about spinning on a roundabout. This is not longer a matter simply of linear motion, but introduces the concept of angular momentum.

So if Weight (a force) = mass x gravitational acceleration, decreasing gravitational acceleration will decrease weight

 

[chocchillimango]

So if Weight (a force) = mass x gravitational acceleration, decreasing gravitational acceleration will decrease weight

mass remains constant so yes, if the rate of change in velocity (ie acceleration).

However, the rate of acceleration due to gravity on earth does not change so weight is relatively constant.

I'm not sure how terminal velocity is even relevant to this discussion.

 

[DREADLIFT]

I lift things up and put them dauwn.

 

[moons]

Weightlifting female physicist?