When it comes to measuring the "hardness" of a material, most tests are distinctly low-tech and basically involve pressing a diamond tip into the surface and measuring the size of the dent produced.

All objects in the absence of air resistance (friction) fall at the same rate regardless of their mass. Due to gravity the speed of an object dropped from rest from a height will increase at the rate ...

Every activity has a value called a "MET value" which calculates the energy required for that activity. Multiplying MET value by weight in kilograms tells you calories burned per hour. You can look up ...