How will dropping a can from a higher or a lower elevation affect the impact it has on a clay ball?

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If a tank filled with water contains a block and the height of the water above point a within the block is 0.8 meter, what is the pressure at point a?

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