Basic question from well check the handle

[Dumbass5000]

I'm involved in a little debate, and I'm looking for an answer to this ignant question:

If I've got two objects of equal density but differing mass, let's say a 1 pound rock and a 1000 pound rock, and I throw them at 100mph over a surface such as dirt/grass, achieving equal height and contact angle upon impact with each object, will they bounce the same distance? (for the sake of argument we'll assume this is in a vacuum)

I understand that the larger rock will achieve proportionately greater gravitational potential energy, and therefore proportionately greater kinetic energy, but it seems to me that the larger rock would also expend a greater amount of that energy displacing the Earth upon contact than would the smaller, and would therefore generate less reactive energy (I'm sure that's a totally ignorant way to phrase it) to once again propel it skyward.

Thanks for helping out a Dumbass5000.

 

[TuviaDaCat]

I'm involved in a little debate, and I'm looking for an answer to this ignant question:

If I've got two objects of equal density but differing mass, let's say a 1 pound rock and a 1000 pound rock, and I throw them at 100mph over a surface such as dirt/grass, achieving equal height and contact angle upon impact with each object, will they bounce the same distance? (for the sake of argument we'll assume this is in a vacuum)

I understand that the larger rock will achieve proportionately greater gravitational potential energy, and therefore proportionately greater kinetic energy, but it seems to me that the larger rock would also expend a greater amount of that energy displacing the Earth upon contact than would the smaller, and would therefore generate less reactive energy (I'm sure that's a totally ignorant way to phrase it) to once again propel it skyward.

Thanks for helping out a Dumbass5000.

heh, grass and dust, are too complicated to be explained by a theory easly.
lets say you have a surface which has no friciton your rocks.(though i think that friction would roughly give the same answer)
also let's say that the surface is hard, and cannot be deformated.
and let's say that the rocks are perfect spheres.

in such conditions, the rocks whould act like a mirror, the angle you drop the rock on the surface, is the same as the angle it will move after the collusion, and the velocity before and after would be conserved.

but i made lots of assumptions... maybe too much of them, but i don't think a simple theory could explain unsimmetric systems...

 

[charng]

I can provide a response to this question. Firstly, it is important to note that in a vacuum, there would be no air resistance to affect the objects' trajectories. Therefore, in this scenario, the objects would indeed bounce the same distance. This is because the force of gravity acting on the objects is determined by their mass and not their density. So, in a vacuum, where there is no air resistance, both objects would fall at the same rate and thus bounce the same distance.

However, in a real-world scenario, where air resistance is present, the objects' densities would play a role in their bounces. This is because air resistance affects objects based on their surface area, which is influenced by density. So, in this case, the smaller, denser object may experience less air resistance and thus bounce further.

Additionally, the larger rock would indeed expend more energy displacing the Earth upon impact. This is due to the larger rock having a greater mass and thus exerting a greater force on the surface it hits. However, this does not necessarily mean that the larger rock would generate less reactive energy to propel itself back up. This is because the larger rock would also have a greater amount of kinetic energy due to its greater mass, which could potentially counteract the energy lost from displacing the Earth.

In summary, in a vacuum, both objects would bounce the same distance due to the force of gravity being determined by mass. In a real-world scenario, the objects' densities would play a role in their bounces due to air resistance. The larger rock may expend more energy displacing the Earth, but its greater mass could also result in a greater amount of kinetic energy, potentially allowing it to bounce the same distance as the smaller rock.