Pressure

Question 1

What is the formula for pressure?

Answer 1

Pressure = Force/Area

Question 2

What is the unit for pressure?

Answer 2

1 Pascal (Pa) = 1 Newton per sq meter
or
N/units^2

Question 3

What does pressure refer to?

Answer 3

The force pushing on a surface.

Question 4

A solid block of wood has a square base with edges 1m and weights 5,000N. How much pressure does it exert on the floor.

Answer 4

5,000

Question 5

A baseball strikes a catcher’s mitt with the force of 200N. If the area the ball strikes is 0.003 m^2, what is the pressure exerted on the mitt?

Answer 5

6666.67

Question 6

Suppose two women each have a mass of 50g. If one woman is wearing spiked heals and the other is wearing flats, which exerts more pressure with each step.

Answer 6

The one wearing flats is exerting more pressure because the surface area is greater than the one with spiked heels.

Question 7

How does the amount of pressure you exert on the floor when standing differ from the pressure when you are lying down?

Answer 7

The amount of pressure exerted on the floor is less than the amount of pressure when you are lying down. This is because of the greater surface area which spreads the force exerted on a wider area.

Question 8

When does pressure exist?

Answer 8

When two objects are in contact with each other and at the points of contact.

Question 9

What does the amount fo pressure depend on?

Answer 9

Magnitude of the force

Surface area

Question 10

What is atmospheric pressure?

Answer 10

Force exerted on you by the air particles in the year.

Question 11

What are fluids?

Answer 11

Substance that can easily flow (liquid + gas)

They exert pressure on the surfaces they touch.

Question 12

What are balanced pressures?

Answer 12

Pressure on you is equal to the pressure exerted back. (This is why we are not crushed by the weight of air). The fluids in our body exert pressure back.

Question 13

How does air pressure change?

Answer 13

Air pressure decreases as elevation increases. The higher the elevation the less air above so there is less weight for air to support.

Question 14

How does water pressure change?T

Answer 14

As depth increases water pressure increases. As depth increases there is more water above that point, there is also the weight of air on the water. Total pressure is the weight of the water plus the weight of the air above it.

Question 15

What is Pascal’s Principle?

Answer 15

When force is applied in a contained fluid, an increase in pressure is transmitted equally to all parts of the fluid.

Question 16

What is Buoyancy?

Answer 16

Water exerts a buoyant force that acts on a submerged object. The buoyant force acts in the upward direction, against the force of gravity so the object feels lighter.

Question 17

Note: A fluid exerts pressure on all surfaces of the submerged object. The pressure in a fluid increases with depth so the upward pressure on the bottom of the object is greater than the downward pressure on the top. The result is a net force called the buoyant force.

Answer 17

Note: A fluid exerts pressure on all surfaces of the submerged object. The pressure in a fluid increases with depth so the upward pressure on the bottom of the object is greater than the downward pressure on the top. The result is a net force called the buoyant force.

Question 18

How to calculate buoyant force?

Answer 18

Weight in Air - Weight in Water

Question 19

What is Archimedes’ Principle?

Answer 19

A submerged object displaces (or takes the place of) the volume of fluid equal to its volume.

Volume of fluid displaced by object displaced = Volume of object

Buoyant force is equal to the weight of the fluid displaced by the object. If the weight of the object is greater than the weight of the displaced fluid it sinks. (More dense) If the weight of the object is equal to the weight of the displaced fluid it floats. (Less dense)