Maths- Gym for Brainiacs

vizkosity wrote:i have no video, that was just purely my speculation. However, sprinting isn't an endurance exercise either. It's more of a HIIT workout, and your body can use a bunch of power during those excercises. Your heart rate is the result of such thing, but as i stated, it takes more than just mechanics to figure out why.

I never mentionted sprinting with cardio

vizkosity wrote:
Sprinting definitely make you work more than however much squats would, just because of the distance ur body moves, as opposed to someone squatting like 1000 times to match the distance. Plus, sprinting drains your glucose more than burning fat, since it's HIIT.

It burns more sugar than fat at first but at the same time hormones are released which signal to the body to use carbs sparely which makes fat metabolism faster.
It's the best way to lose fat, not just 'weight'

vizkosity wrote:

http://forum.bodybuilding.com/showthread.php?t=108975221&page=1

may shed some light

They missed the crucial part which is genetical predesposition. They conclude that sprinters who squat ridiculious weights are faster because of squats I was able to squat 80kg easily in my first week of weight training Some other people had ridiculious chest strength in bench press ( my weakness).
I'd say max squat strength is an indication of how fast one could run, not the factor which enhances it the most. Of course, if the legs are underdeveloped squating might help reach top speed faster.

vizkosity wrote:
Squating can make you stronger, but not neccessarily faster. Sprinters tend to lose a lot of more weight from fat, ect...while squating can increase your power. Wingers and fullbacks in football can be extremely skinny, yet quick. But anyhow, squating will give you better power and thus, sprint faster providing both have the same mass/endurance

In professional sports, performances is understood differently from bodybuilding where max hypertrophy is the best result. If your skinny footballer squats more than 2x of their weight they're clearly above average no matter how small or big they're.

this fully validates the minimal stats study ive done

seems like you've already answered ur question

@fatman, reduce mass is greatly useful for center of mass problems Perhaps, too useful

Muon is a particle, same charge as electron, just a lot heavier

vizkosity wrote:seems like you've already answered ur question

@fatman, reduce mass is greatly useful for center of mass problems Perhaps, too useful

Muon is a particle, same charge as electron, just a lot heavier

Nope, I have rough figures only. No idea about exact forces
We only cleared up the body weight part and the biolofical part. I'll look up that documentary

the forces are just...well, very complicated. If you can, u can imagine us as spheres and calculate the projectiles. I dont really think forces are the main thing here, rather, it's the impulse/work/energy/power/duration that cause the difference

Forces are the main thing here. Whether an exercise causes hypertrophy or one would break his toes or not with too much force is about the single stride in sprinting.
Impulse/work/duration is reasonable for machines

starts around the 9 minute mark but u can watch the whole thing as well, its interesting. this is the 2nd part of the episode u can find the first one somewhere in the side or just do a search for it.

Awesome find

he mentioned power/energy/glucose...those are indeed related to force.
Energy is almost the same as "work" and they are not only used in machines. What work/energy is are just force over a certain distance, the dot product of force and distance. Impulse is the change in momentum, which Newton wrote in his 2nd law originally as " F= dp/dt", not F = ma. F =ma is just another version of it, but F is actually the change of momentum over time. F = ma breaks down when your mass is constantly changing (rockets, dripping sand).

Power is not just for engines, it is indeed, work/time. or Energy/time. If you put in a ton of energy over a short period of time, you're generating a lot of power. Human body is capable of creating so much power in short burst that it's amazing. Sprinting uses a lot of power contrary to your believe.

In fact, many physicists don't look at one mechanics problem in term of forces. Sometimes (or perhaps too often), energy/impulses/power can give an easier answer (imagine conservative force field, where the curl is 0, i think you understand that concept since you study math).

The video also highlighted more on power, energy, and glucose, rather than just simply "forces". Squating and sprinting are two different excercise. Sure, squating requires more force, but it doesn't need as much "power" and effort (or work) compared to sprinting (not even a close call).

You can think of it as pushing a big wall vs. lifting a dumbell. If the wall doesn't move AT ALL, you exert no work on it, however you would have a greater force than doing dumbells. But not everyone pushes the wall for muscle do they?

In a sense, squating saves you a lot more time and effort if you do it with the right weight, but the reason why sprinting kills your legs....well, it's not "just" because of the force relation. You can exert a bunch of force, but if you are not going anywhere with it, you will not exert any power/energy/ or deplete any glucose in your muscle.

That's all i can tell you, better refer to a biologist or chemist for a better answer. But if one claims that it's only force that is related, i call that bullshit. You can have him/her to come here and debate with me about that.

vizkosity wrote:he mentioned power/energy/glucose...those are indeed related to force.
Energy is almost the same as "work" and they are not only used in machines. What work/energy is are just force over a certain distance, the dot product of force and distance. Impulse is the change in momentum, which Newton wrote in his 2nd law originally as " F= dp/dt", not F = ma. F =ma is just another version of it, but F is actually the change of momentum over time. F = ma breaks down when your mass is constantly changing (rockets, dripping sand).

Power is not just for engines, it is indeed, work/time. or Energy/time. If you put in a ton of energy over a short period of time, you're generating a lot of power. Human body is capable of creating so much power in short burst that it's amazing. Sprinting uses a lot of power contrary to your believe.

In fact, many physicists don't look at one mechanics problem in term of forces. Sometimes (or perhaps too often), energy/impulses/power can give an easier answer (imagine conservative force field, where the curl is 0, i think you understand that concept since you study math).

The video also highlighted more on power, energy, and glucose, rather than just simply "forces". Squating and sprinting are two different excercise. Sure, squating requires more force, but it doesn't need as much "power" and effort (or work) compared to sprinting (not even a close call).

You can think of it as pushing a big wall vs. lifting a dumbell. If the wall doesn't move AT ALL, you exert no work on it, however you would have a greater force than doing dumbells. But not everyone pushes the wall for muscle do they?

In a sense, squating saves you a lot more time and effort if you do it with the right weight, but the reason why sprinting kills your legs....well, it's not "just" because of the force relation. You can exert a bunch of force, but if you are not going anywhere with it, you will not exert any power/energy/ or deplete any glucose in your muscle.

That's all i can tell you, better refer to a biologist or chemist for a better answer. But if one claims that it's only force that is related, i call that bullshit. You can have him/her to come here and debate with me about that.

I'm getting where you're coming from. I think you felt offended by my example.
Look, a foot isn't an unbreakable unit. If you apply too much force at once it'll break or some bones of it. Not the power in physics terms or meaning determine the outcome but the forces which work locally in a single stride.
Same story with hypertrophy. If you don't apply enough force in each rep of an exercise muscles won't grow. You'd be doing cardio workout instead of resistance training.
Did you get my point or my fixation on exact forces?

You're right about exhaustion. Power is instrumental in exhaustion. That's my fault. I wasn't clear enough with what I meant under being done after sprints. My accent was on being done in terms of resistance training not in the categiory endurance exhaustion.

MOAR maths questions please

RealGunner wrote:MOAR maths questions please

Never saw you crave for maths questions before
I'll come up with something soon.

just bored really

RealGunner wrote:just bored really

My youngest cousin is in highschool. She asked me via facebook to solve this for her:

The area enclosed between f(x)= x² and g(x)= 1 -kx² is equal to 2/3. Find the numerical value for k!

She needs it on Tuesday. Have fun

you sure there is no graph involved in the question ? It is area between the cruve isn't it ?

RealGunner wrote:you sure there is no graph involved in the question ? It is area between the cruve isn't it ?

I meant the area between the graphs of f(x) and g(x) I didn't calculate anything. Off the top of my head it should look somewhat like this:




The red area is equal to 2/3.

but the x values should be defined in the graph lol

RealGunner wrote:but the x values should be defined in the graph lol

You could determine them by yourself

k = 5 ?

Babun wrote:
My youngest cousin is in highschool. She asked me via facebook to solve this for her:

The area enclosed between f(x)= x² and g(x)= 1 -kx² is equal to 2/3. Find the numerical value for k!

She needs it on Tuesday. Have fun

k=0

I got k =4.5 by assuming the area enclosed to be an ellipse.

Then area = pi * a * b.

a = 1/2 and b = 1/(k+1)^(1/2)

Equating this to 2/3 you get k = 4.5 approximately.

RealGunner wrote:k = 5 ?

urbaNRoots wrote:

Babun wrote:
My youngest cousin is in highschool. She asked me via facebook to solve this for her:

The area enclosed between f(x)= x² and g(x)= 1 -kx² is equal to 2/3. Find the numerical value for k!

She needs it on Tuesday. Have fun

k=0

I don't know whether you two are right or wrong. Write down your claculations for me to follow

kiranr wrote:
I got k =4.5 by assuming the area enclosed to be an ellipse.

Then area = pi * a * b.

a = 1/2 and b = 1/(k+1)^(1/2)

Equating this to 2/3 you get k = 4.5 approximately.

Ellipse isn't exact. I'd say determinte the interval first:
f(x) = g(x)
If everything goes right you should be able to get an intervall for graph intersections. The rest is pure calculation ( I'd do it myself if I weren't freaking busy)

Yeah, i did that and integrated over the interval.

The interval is -1/(k+1)^(1/2) to +1/(k+1)^(1/2)

But the integral of g(x) minus integral of f(x) over the interval gets very complicated to solve for k.

I only tried it once and then decided to assume it is ellipse. I may be making some mistake. I will try again when i get the time, but if you solve it before, tell us the answer.

kiranr wrote:Yeah, i did that and integrated over the interval.

The interval is -1/(k+1)^(1/2) to +1/(k+1)^(1/2)

But the integral of g(x) minus integral of f(x) over the interval gets very complicated to solve for k.

I only tried it once and then decided to assume it is ellipse. I may be making some mistake. I will try again when i get the time, but if you solve it before, tell us the answer.

That's why I don't want to solve it

urbaNRoots wrote:

The integral over g(x) should be bigger than over f(x)
See my draft in post #494. I mean it should be integral over g(x) - f(x) instead of f(x) - g(x).

Arghh!!!!

Ok I did this shit again and it got me k=-1/2. If I'm wrong I'm not doing it again