15. In Problem 15: If that 25.0 kg rock is dropped from a height of 10 m, A) When the rock
is halfway down (5 m), what kind(s) of energy does the rock have and how much? B) What is
the velocity of the rock halfway down? C) What is the velocity of the rock just before it hits the
ground?

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