chapter 6 - pressure

Question 1

pressure

Answer 1

force exerted by an object per unit area

Question 2

density

Answer 2

mass per unit volume

Question 3

conversion between kg/m3 to g/cm3

Answer 3

1000 kg/m3 = 1 g/cm3

Question 4

pascal’s principle

Answer 4

if a pressure is applied to a trapped liquid, the same pressure is transmitted to all parts of the liquid

Question 5

explain the crushing can experiment

Answer 5

• when heating the water until its boiling point, it produces steam that rushes out of the can, removing some air from the inside, creating a partial vacuum
• when removing the can from the heat and screwing the cap on, the air inside is trapped and no air can enter or escape from the can
• when placing the can under running water, the steam inside condenses, removing more gas
• the can crumples as the atmospheric pressure is the surrounding is larger than the pressure inside the can as a partial vacuum has been created inside
• humans are not crushed like the can as the pressure in our body (eg. blood pressure) is balanced with the atmospheric pressure

Question 6

explain how to use a manometer to find the pressure of a gas

Answer 6

• if source column taller than open column, pressure of gas = atmospheric pressure - mmhg
• if source column shorter than open column, pressure of gas = atmospheric pressure + mmhg

Question 7

how does the molecules inside the cylinder create a pressure

Answer 7

the small air molecules are moving randomly collides with the wall of the container. when an air molecule collids with the wall, it exerts a force on the wall. when multiple of the gas molecules collide with the wall, the force builds up as the particles collide with a greater impact. the total force exerted per unit area is the pressure exerted by the gas.