Configure pilot weight (parachute)

[benih]

And it’s nice efficient weight loss diet haha

[V12]

I bet Galileo is spinning in his grave.

Newton, not Galileo...

[S&J]

Well now he's definitely spinning

[MariuszXC]

In Physics free fall describes motion of objects which are under sole influence of gravity.
It is explicitly stated, that free-falling objects do not encounter air resistance.

Just sayin'

[S&J]

I think we have a definition issue here.

Initially I replied to a parachutist that was falling faster with increased weight.

Clrealy Galileo nailed this.

However with parachute deployed a parachutists glides with the aide of lift and drag, here the weight does have an effect.

So can we please call a parachutist without cute deployed falling and with gliding to save confusion.

[MariuszXC]

I think the thread became somewhat 'tongue in cheek' at some point

Anyway, falling parachutist with or without a parachute[*] deployed is basically the same thing - in both cases air influences the fall, so it is not a free fall in Physics sense.

A fun fact is, that after initial acceleration the speed of a falling human will stabilise roughly around 160-180 km/h[**] (if memory serves) due to air resistance and gravity forces cancelling themselves out. Of course it depends on a number of factors influencing the drag coefficient (for example if arms are extended or on type of clothing worn).

So, answering tongue in cheek, yes, it depends on shape and form. A heavy parachutist may fall faster if (s)he is more round-ish (shall we say.. less aerodynamically challenged?)


[*] - modern gliding parachutes will complicate the picture a bit, so let's stick to old style round canopies here
[**] - at standard air density

[TheEagle]

@S&J: Galileo now is definitely turning in his grave … his research area was astronomy, not physics …

[D-ECHO]

@TheEagle: https://mypages.iit.edu/~smart/martcar/ ... esson2.htm

but I think this discussion might be rather pointless, as the "free fall" a human falling through atmosphere experiences is dependent on air drag (as already explained above).

[S&J]

Thanks D-echo for the link, saves me having to post a response to eagle.

I think there also are two different types of parachute.

1) Drag chute (as in WWII)

2) Lift/glide chute (as in 'red devils')

I'd say weight would have no effect when using 1) but will have an effect when using 2)

[erik]

I'd say weight would have no effect when using 1) but will have an effect when using 2)

I beg to differ, provide the chap with a handkerchief en the poor fellow will drop considerably faster.
Drag is just another word for lift when falling/gliding just under gravity.

Erik

[S&J]

Yeh but know you're changing the size of the drag making device not the size of the man.

Lift and drag are vectors of the resultant. By convention lift acts 90 degs to the wind whilst drag is aligned with the wind. So yes the resultant and drag can overlay with zero lift. But with a glide chute and any lateral motion there'll be some lift and drag will no longer overlay the resultant.

[erik]

True.

Erik

[amue]

A heavier body falling through air will reach a higher terminal velocity than a lighter body (assuming equal presented area and drag coefficent and neglecting any lift):

At terminal velocity the gravitational force equals the drag force:

F = D with F = m * g and D = 1/2 * rho * v^2 * A * C_d.

Transforming the equation yields:

v = sqrt((2.0 * g * m) / (rho * A * C_d))

That means

v is directly proportional to sqrt(m).


I think Galileo can continue to rest in peace.

[TheEagle]

@D-ECHO: okay, thanks, is that Galileo a different person than the great astronom ? Or did Galileo Galilei also study physics ?

[wkitty42]

yes, that's the same Galileo... he was into a lot more than just physics