Where does the potential energy in the lever arm (of a trebuchet) come from?

Who was the first scientist to measure speed as distance over time?

The freezing and boiling point of a substance changes as the air pressure around it changes. for example, at a lower air pressure (higher altitude) it is easier for water molecules to escape from liquid into the air. in a high altitude city such as denver, colorado compared to a sea-level city such as houston, texas, water

What part of the ear is names after tools, such as the hammer and the anvil?