This is the second installment of our “What is…?” series.
During these months of quarantine, a lot of us have probably thought once or twice that we have been putting on some quarantine-weight. And while that is true (or not, for you, athletic reader) what is actually happening, is that you body is acquiring mass. A somewhat trivial difference, you may say, as weight is just the force inflicted by gravity on to some body. And it strikes me as a funny thing that in our everyday physics, everything comes intuitively to us, force, speed, acceleration, rotation stuff. Everything -but mass. It feels intuitive, but the more you think about it, the more you will end up asking yourself… What is mass?
Many Body Physics 