Solved

# Einstein's formula and springs

Posted on 2004-04-28

Einstein's famous formula says that E = mc^2, meaning that there is a conversion relationship between mass and energy.

Let's say we have combination spring and latch, and we can determine the mass of the spring+latch to an arbitrary degree of precision. Then we compress the spring and latch it in the compressed state, thereby storing energy in the compressed spring. Since there is a relationship between mass and energy, does this mean that the compressed spring+latch will mass more than the uncompressed spring+latch?

Similarly, does a spinning gyroscope mass more than a stationary gyroscope?

How about a charged battery vs. a discharged battery?