Inquiring Minds


Questions About Physics

Accelerating massive objects

Dear Mr. Krupa,

To accelerate an object so its mass is increased by 1% then gamma, the "time dilation factor" will be simply 1.01. That is equivalent to accelerating the mass to a velocity of 14% of the speed of light or 42,000 km/sec.

A 10% increase in mass corresponds to a gamma of 1.10 or a velocity of 42% of the speed of light.

The amount of energy required is ENORMOUS! Remember E=mc2. The "exchange rate" between energy and mass is a very large number. So when you turn mass into energy (nuclear reactors, nuclear bombs) you get an enormous amount of energy while using up a small amount of mass.

But that also works in the other direction. To create even a small amount of mass requires a very large amount of energy.

Take your 1 kg mass and increase it by 1%. In other words you want to move it fast (14% of the velocity of light) so that its (relativistic) mass is increased by 1% or 10 grams.

How much energy is required to create 10 grams? Here are a few numbers I worked out:

-- approximately the electrical energy required to run Fermilab for one year -- the kinetic energy of 3 MILLION, 1000 ton freight trains all moving at 50 miles/hour -- the explosion of 300 kilotons of TNT (or about 15 Hiroshima sized bombs).

Let me know if you have further questions.

Sincerely, Dr. Ernest Malamud

Back to Questions About Physics Main Page


last modified 2/16/1999   physicsquestions@fnal.gov

FRLsDFx9eyfrPXgV