P11-Pressure

Question 1

What is meant by the term fluid

Answer 1

A liquid or gas

Question 2

How to calculate pressure

Answer 2

Pressure=force/area

Question 3

What is pressure measured on

Answer 3

Pa-Pascals
N/m^2

Question 4

How to calculate Pressure in liquids

Answer 4

Pressure=heightxdensityxgravity

Question 5

Density of sea water

Answer 5

1050 kg/m3

Question 6

Gravity

Answer 6

9.8 n/kg

Question 7

What is upthrust

Answer 7

A force which acts upwards

Question 8

Kpa to pascals

Answer 8

1Kpa =1000 pa

Question 9

How do you calculate fluid pressure at the surface?

Answer 9

Pressure = Force normal to a
surface area / area of the surface

Question 10

What happens when you go higher/increase your altitude

Answer 10

The density of the air decreases

Question 11

What is density

Answer 11

A measure of the compactness of a substance

Question 12

What happens if a liquid is more dense

Answer 12

There are more particles it has in a certain apace

Question 13

What happens if an object floats

Answer 13

Weight=upthrust

Question 14

What happens if an objects weight is more than the upthrust

Answer 14

The object sinks

Question 15

What happens if an object is less dense than the fluid its placed in

Answer 15

It weighs less than the equivelant volume of fluid.This means it displaces a volume of fluid that is equal to its weight before its completely submerged

Question 16

Define pressure

Answer 16

The force per unit area exerted on a surface

Question 17

A 10 N force is exerted on a 20 cm? piston. If this is connected to a 60 cm? via a
hydraulic system, what will be the force produced?

Answer 17

30n
10/20=0.5
0.5x60=30n

Question 18

Why does pressure increase with depth

Answer 18

There is a greater mass of water above the point, therefore the weight of water above that point is greater which applies a compression force.

Question 19

Why does pressure increase with density

Answer 19

There are a greater number of particle in a given volume so there are more frequent collisions of particles with a surface increasing the force over a given area.

Question 20

Explain upthrust in terms of pressure

Answer 20

There is greater pressure on the bottom surface of an object than on the top surface.This creates a resultsnt force upwards;the upthrust

Question 21

What causes atmospheric pressure

Answer 21

Air molecules colliding with a surface. At each collision they apply a force normal to the surface

Question 22

How are atmospheric pressure and altitude related

Answer 22

As altitude increases, pressure decreases. This is a non-linear relationship.

Question 23

Why does atmospheric pressure decrease with an increase in height?

Answer 23

As altitude increases, the size of the column of air above a point decreases, reducing the weight of the air above that point
Also as altitude increases, the air becomes less dense, which means that air particles collide less frequently with the surface.

Question 24

How are the pressure and volume of gas held at constant temperature related?

Answer 24

Inversley proportional

Question 25

When work is done on a gas, what happens to the gas?

Answer 25

The internal energy increases and i it can also cause an increase in temperature.

Question 26

How does decreasing area affect pressure?

Answer 26

Decreasing area increases pressure

Question 27

Why does liquid pressure act in all directions?

Answer 27

Particles move in all directions and exert equal force.

Question 28

At what height does atmospheric pressure reach near zero?

Answer 28

50km above sea level

Question 29

What is pascals principle

Answer 29

A change in pressure in a fluid is transmitted equally in all directions.

Question 30

Define boyles law

Answer 30

Boyle’s Law states that for a fixed mass of gas at constant temperature, the pressure (P) and volume (V) are inversely proportional.

Question 31

How to calculate boyles law

Answer 31

P1xv1=p2xv2

Question 32

A gas has a pressure of 300 kPa and a volume of 2 m³. The gas is compressed to 0.5 m³ at constant temperature. Calculate the new pressure. Example question

Answer 32

P1xv1=p2xv2 300x2=p2x0.5 600/0.5=12000kPa

Question 33

Explain how Boyle’s Law applies to a scuba diver ascending from deep underwater.

Answer 33

pressure and volume are inversely proportional,As a scuba diver ascends, external pressure decreases,Because of Boyle’s Law, the volume of air in the diver’s lungs increases,If the diver ascends too quickly, the air expands too much, possibly causing lung damage,To avoid this, divers exhale slowly while ascending to release expanding air.

Question 34

Two examples of elastic objects

Answer 34

Spring and a spondge

Question 35

How do you calculate the extension of a spring?

Answer 35

Length of spring with force applied - original length of spring

Question 36

What does a directly proportional relationship look like on a line graph

Answer 36

Straight line with a gradient passing through (0,0)

Question 37

Define pressure in a column

Answer 37

The pressure in a column of liquid is equal to the product of the liquid’s density, the height of the column and the gravitational field strength.