Yes, that is right, Moir giving points! 15 in fact!

 

*gasps*

 

All you have to do is solve this simple thought problem I need ya'll to run.

 

 

Let's say you have a small wooden block.

 

I want you to tell me how you would find the mass of this object without actually 'massing' it. That means no scales, balances, etc.

 

Shoot.

Use your magic machine to convert your block to pure energy. Since your machine is magic, it can measure the amount of energy 'created'. Apply e=mc^2 to find mass.

 

 

 

What? Magic doesn't count?

 

 

 

I presume I can't use a force meter, or I could just measure the weight against a known acceleration. :(

 

 

 

Or you can make like Cavendish and measure mass with a torsion balance for kicks and giggles, but that's excessive. EXCESSIVE.

I like Zyr's magic example

 

GO FOR IT!

Maybe you can... errhh... *punches everyone, grabs the log and makes a run for it*

I can think of two ways to do this off of the top of my head.

 

Think Newton.

Are you saying the rate of which an object is in freefall is relative to it's mass?

But what about when you drop a bowling ball and a ping pong ball off of the tower of pisa at the same time?

The remarkable observation that all free falling objects fall with the same acceleration was first proposed by Galileo, nearly 400 years ago. Galileo conducted experiments using a ball on an inclined plane to determine the relationship between the time and distance traveled. He found that the distance depended on the square of the time and that the velocity increased as the ball moved down the incline. The relationship was the same regardless of the mass of the ball used in the experiment.

What do all of those letters mean?

I can think of two ways that can give a decent approximation.  But I hate points, so lets not mention them.

 

(psst....if someone likes points, they may wanna mention a simple experiment where you send the block of wood of an unknown mass at a known acceleration...hitting it against another object with a known mass.  You do this on a frictionless plane (or near frictionless) and measure the acceleration from the object of known mass.  Then using the equation that m(wood)a(wood)~=m(known)a(known) you have it.)

 

(Or....you can take a similar sample of the wood with a known mass and put it in a calarimitor.  (fine, my spelling is way off on this, but I don't care.  It is still early for me.)  Once you can see how much energy is given off, you then stick your unknown block of wood in and measure the energy.  By the equation (energy of unknown)/(energy of known) *(mass of known) you get (mass of unknown))

 

May be more creative ways, but I've been awake for 20 minutes.  Not even had caffeine yet.

Pukah got it.

 

You could also have used density :P

 

And Jelly, Inertial mass is equal to graviational mass, which is not mass :P

(I didn't get it!  I abstain!  I will now abscone so someone else can get the points)

You want the points, Pukah. YOU WANT THEM.

I think he does too.

umm, you could have used the density formula? I figured if you couldn't know the mass then you couldn't know density or volume either...

By knowing the volume, you can get the mass if you have a source of the density...so taking a sample of the same kind of wood, and getting density from that.

 

You could find the density by putting it into water and watching how far it submerges :P

I considered that, but it seems imprecise.

If you take your measurements close enough it won't.

 

You don't 'see' how far it submerges, you measure displacement :P

yeah, but when you said no scales and ect. i figured no measuring instruments, either. same for a graduated cylinder large enough to measure the wood.

i was going to say whack it against some unsuspecting fuls head then measure the dent........

I was gonna say pee on it, then cover it in chocolate and tell someone it's a Hershey Bar.

 

Dunno what'd do for mass, but it would be funny.

:)

 

hey, I just learned about these fancy newton laws at skul

 

if only I had known to utilize them!

 

*shakes fist at sky*