Physics question - gravity

[Usarka]

There's a physics question on the daily stuff quiz today

If you dropped three spheres weighing 1kg, 2kg and 3kg, at the same time from the same height, which would hit the ground first?

The obvious (and deemed correct by stuff) answer is "all at the same time".

But I was thinking... But don't all objects with mass create gravity?

In which case the larger mass object will create an infintessimally greater amount of gravity than the others, therefore the 3kg object will hit the ground first by a fraction of a fraction of a nanosecond.

Have we been lied to as children????? Bastards.

[MSTRS:Me]

You also need to factor in the extra drag created by the heavier object being physically larger. Maybe.
What happens when objects of the same size, but differing mass, are dropped?

[davereid]

There's a physics question on the daily stuff quiz today

If you dropped three spheres weighing 1kg, 2kg and 3kg, at the same time from the same height, which would hit the ground first?

The obvious (and deemed correct by stuff) answer is "all at the same time".

But I was thinking... But don't all objects with mass create gravity?

In which case the larger mass object will create an infintessimally greater amount of gravity than the others, therefore the 3kg object will hit the ground first by a fraction of a fraction of a nanosecond.

Have we been lied to as children????? Bastards.

Acceleration due to gravity actually depends more on what the weight is accelerating towards than the mass of the weight itself.

For example, heavy weights accelerating towards MY foot actually accelerate faster than heavy weights accelerating towards YOUR foot.

This also applies to vehicles.

Acceleration due to value is the rule here.

The expensive motorcycle will accelerate exponentially faster, and more often towards the ground than the inexpensive motorcycle.

[onearmedbandit]

I was always under the assumption that all objects are affected by gravity equally, just on earth due to our atmosphere we don't see that in experiments. Unless of course you conduct the experiment in a vacuum. Myth Busters did an episode on Space the other day, they used one of NASA's vacuum chambers, and they dropped a feather and a hammer at the same time, and of course they both touched the deck at the same time.

[doc]

So fat skydivers fall faster ? Isn't it something to do with reaching terminal velocity ?

[SMOKEU]

So fat skydivers fall faster ? Isn't it something to do with reaching terminal velocity ?

If we're talking about such large distances, then a fat skydiver will have a lot more surface area, and therefore air resistance, in comparison to a skydiver whom is not of such a large carriage.

[gazmascelle]

does the same apply to number twos? What if its solid or liquid?

[avgas]

If your bigger mass is, I dunno.....the size of the moon
yes.

3kg's has fuck all gravity, so in terms of timing how fast it falls - dunno if your will be able to measure it.

I think the russians tested this with Mir, and their space station had like 1 millionth of a G or something.

[avgas]

So fat skydivers fall faster ? Isn't it something to do with reaching terminal velocity ?

Nah - its just looks like that when you see the mess on the ground.
They just fall with more momentum.

[bogan]

heavier objects have a higher force generated by gravity, F1=ma. However wind drag is proportional to size and shape and velocity squared, so (simplified) F2=v^2*size*shape, when the Forces are equal you have terminal velocity. When not you get an acceleration of a=(F1-F2)/m. So if the spheres are same size the heavier one will hit ground first.

[aprilia_RS250]

Tie the three balls up together and drop them together.

What would happen? Would the time taken to drop be faster as it's now heavier than the time it took the 1kg ball to drop?

[Juzz976]

The 3kg would have 3 x the Gravitational force accelerating it towards the earth, but because its 3 x the mass the force needs to be 3 x to get the same acceleration. The 3kg will impact with more energy however.

Generally you neglect aerodynamics friction blah blah unless the duration of acceleration causes the object to approaches terminal velocity or moving through a viscous substance. Then there is more maths but not too hard just invloves drag co effcient, displacement and dens
ity of medium in which object is travelling through.

A mercury ball entering our atmosphere would be a good 1. initial speed, rate of increase in grav acceleration (getting closer to earth), temperature rise causing expansion creating more drag...
Shit getting excited now...memories of school in all...

[Juzz976]

oh yeh increase in air density as approaches earth.

I must be bored, real bored.

[pzkpfw]

What we should do is spend a ton of money sending someone to the Moon, where they can drop a feather and a hammer at the same time, to see which hits the Moon first.

[Juzz976]

What we should do is spend a ton of money sending someone to the Moon, where they can drop a feather and a hammer at the same time, to see which hits the Moon first.

The hammer, the hammer and feather would pull into eachother due to the gravitational force between them. The feather would move toward the hammer faster as the same force applied to a smaller mass. The feather is now taking a longer route towards the moon as its vector has shifted more than the hammer.

Maybe the feather, if the moon is far enough away the feather will collide with the head of the hammer thus causing the hammer and feather to spin (very slowly) the feather will have an affinity towards the centralised mass (hammer head) and the hammer may possibly land ontop of the feather.