Why is a mchaine's actual output work always less than its input work?

What is a good example of instantaneous speed

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

The amount of potential energy possessed by an elevated object is equal to