Is there proof that two objects of same mass require same energy to move even if they are of different density

Question

I would swear that with two objects with the same mass but one is 100000% more dense then the more dense object would require more energy to be moved.

Is there physical proof of this? Proof through experiments rather than proof through theory?

?Try it for yourself. Get two substance of different density. Weigh them on a scale and make sure they have the same weight (which would mean they have the same mass). Get something on wheels you can set the substances on and can push"


I wouldn't have anywhere near the sensitivity in equipment to measure the difference needed. I doubt anyone does. The difference in required energy would be extremely, extremely small. The tiny variations of earth gravity would screw up the experiment.

Maybe if you were moving an aircraft carrier and a mass equal to the aircraft carrier but in the size of a suitcase. Then you may be able to measure the differences but even then the amount would be extremely small.

Really the best way to see this occur would be movement and impacts in space.
I believe it would be near 100% impossible to test this on earth because the differences would be so small that the interference from earth gravity would screw up the readings.

The experiment would have to be done in a zero G enviroment w/vacuum.

http://www.fourmilab.ch/cship/timedial.html

This time dilation chart would be the same but instead of time dilation it would also work on the density issue.

As you see in the graph you would have to go to extremely massive objects of different densities to find a big enough reading to read.

Physcial proof! You guys just keep coming up with formula's. I don't believe any formula unless there is 100% physical proof that it is correct.

On this issue density is missing in the equations because there is no way of currently testing it. You are unable to experiment with it on earth because the measurments are so small that earths own gravity would mess up the results.

Answer 1

In a vacuum, in the absence of friction, the energy required would be the same.

The "proof" is simply the newtonian expression for kinetic energy (energy of movement):

K=0.5 mass * velocity^2

The only variables are the mass and the velocity, not density.

Answer 2

Try it for yourself. Get two substance of different density. Weigh them on a scale and make sure they have the same weight (which would mean they have the same mass). Get something on wheels you can set the substances on and can push. A skateboard might work. Then push the board with the same amount of force and see if the denser object takes more energy to move. Obviously if two things is the same weight (mass really), it will take the same amount of energy to move no matter what their density.

Answer 3

d = m/v so increase mass you increase density eg 20/10 to 40/10 d= 2 & 4 respectively : increase; increase vol you decrease density eg 80 / 40 to 80 / 80 = 2 & 1 respectively : decrease.

Answer 4

Yes, it is called a weight scale. Equal masses are also equal weight at the same altitude, so a spring scale, or other weighing mechanism would weigh both objects as the same weight.

Answer 5

in ideal condition like vaccum ...yes they will require same energy

its proof is the formula 4 kinetic energy which says k.e=0.5*m*v^2