Balls puzzle.

Sakha

You have 2 balls. Both are identical in size and mass, but one is made of gold and is hollow,the other is not hollow and made from titanium. Find out which is which ball, and lets say both are covered with a black paint that is anti reflective, heat/electricity insulator. You can't use any measurement device, nor hitting, damaging or breaking the ball..

P.S: There's a really simple way.

DaveC426913

Knock them? One will sound hollow?

Sakha

Mmm.. lets say the paint is anti-acoustics.

lisab

Sakha

wheew.. you're fast..

DaveC426913

Around here, we like our women that way.

regor60

drop them in water. the hollow one will bob higher.

oh..same mass, never mind

Sakha

Nice try.

arildno

Remove the paint?
(This as an alternative to lisab's suggestion)

some_one

oohh rigid bodies thats realy good

some_one

put them in a bucket of water
they vary in density
the gold will pull out more water
am i correct?

Sakha

As I said, you can't damage nor break the ball, and removing the paint would be considered damaging. But yeah, lisab's answer is right.
Both would pull same amount of water because both are same size and mass, so they have same volume and density.

arildno

I think black is a damaging colour, I'm merely prettifying the balls..

some_one

aaahhh disregard it
you sayed that the gold ball is hollow

Sakha

No, imagine a gold sphere as an "o" the black line is gold and the white is hollow... The titanium sphere is all solid.

some_one

if you shoot them out of a cannon
the gold ball will not fly in a steady trajectory
because its hollow

in order to fly in a steady way you need to have a full ball

because from my knowledge
the AK bullets have a shifted center of mass
which make them highly unstable
and when they hit a person
instead of going forward
they are starting to swirl inside the victim

am i correct?

arildno

The middle of the gold ball is empty, some one, it is hollow.

The hollowed gold ball can perfectly well have the same size and mass as the compact titanium ball