Why did early scientists have to guess and
theorize about the structure of atoms?

In the first law of thermodynamics, triangle e=q-w, what does q stand for

Estimate the schwarzschild radius (in kilometers) for a mini-black hole formed when a superadvanced civilization decides to punish you (unfairly) by squeezing you until you become so small that you disappear inside your own event horizon. (assume that the your weight is 50 kg)

Awave has a wavelength of 7 mm and a frequency of 19 hertz. what is its speed?