Émilie du Châtelet
Faster means stronger — but how much stronger?
That time, that place
A French noblewoman. She could not attend a university and could not join the Academy of Sciences. The story goes that she entered the cafés where mathematicians gathered dressed as a man.
Why this question
Scholars had been arguing over one thing for years: what is the force of a moving body proportional to? One camp said speed; the other, the square of speed.
Argument alone would never end it. Du Châtelet looked for the experiment.
What was found
In the Netherlands there had been an experiment: drop heavy balls into soft clay and measure how deep they sink.
A ball moving twice as fast sank not twice as deep but four times. Three times as fast, nine times.
So motion contains a quantity proportional to the square of speed — what we now call kinetic energy. She assembled the case and argued it.
She also translated Newton's Principia into French with extensive commentary. That translation remains the standard French edition today.
The force of motion was simply proportional to speed
Impressions in clay deepening with the square of speed
She died at forty-two following childbirth; the Principia translation appeared posthumously