Pressure & Hooke's Law

Question 1

Define pressure

Answer 1

The perpendicular force acting per unit area on an object

Question 2

Pressure Formula and units

Answer 2

Pressure= Force/ Area
Nm‐² or Pa

Question 3

Convert 1Nm² to Pa

Answer 3

1Nm²= 1Pa

Question 4

Where and how does a fluid exert its pressure

Answer 4

It exerts a pressure in every direction and a pressure perpendicularly to the surface it touches

Question 5

Define atmospheric pressure

Answer 5

The pressure that an area experiences due to the force exerted by atmosphere

Question 6

Gauge Pressure

Answer 6

The pressure of an enclosed volume fluid, relative to atmospheric pressure

Question 7

Absolute pressure =

Answer 7

Gauge Pressure + Atmospheric Pressure
𝑃 = 𝑃𝐺 + 𝑃0

Question 8

What are the four basic principles that dictates the magnitude of the pressure in a liquid

Answer 8

1. The pressure at a given depth in a fluid is equal in all directions
2. The pressure at any given depth any fluid is independent of the shape of the container in which the fluid is held
3. Pressure Acts at right angles to the surface containing the fluid
4. When a pressure is applied to a fluid this pressure is transmitted equally in all directions

Question 9

State Hooke’s law

Answer 9

The extension of a material is directly proportional to the applied force producing the extension providing the elastic limit is not exceeded

Question 10

Hooke’s law formula

Answer 10

𝐹 = 𝑘 × ∆𝐿
Fs = kL

Question 11

What is meant by a material demonstrating elastic behavior?

Answer 11

Material demonstrating elastic behavior means the material returns to its original size and shape when the forces stretching and deforming it are removed

Question 12

What is a plastic or inelastic material?

Answer 12

Material that stays deformed after you remove the force that is acting on it

Question 13

When reading a graph of force against extension which spring would be the stiff spring on which one which stretch more

Answer 13

This spring with the greeter slope would have a larger spring constant (k) and therefore stretch less

Question 14

Define elastic potential energy

Answer 14

The energy stored in the spring when work is done on it to stretch or compress it

Question 15

State the elastic potential energy formula

Answer 15

PEs =(½)kL2

Question 16

What does the spring constant measure?

Answer 16

How stiff the spring is

Question 17

The larger, the spring constant

Answer 17

The stiffer the spring

Question 18

What is the spring constant unit?

Answer 18

Nm-1

Question 19

What is the spring constant unit?

Answer 19

Nm-1

Question 20

Define stress

Answer 20

The force acting per unit cross-sectional area

Question 21

State stress, formula and units

Answer 21

𝜎 = 𝐹/𝐴

Question 22

Define strain

Answer 22

The ratio of the extension to the original lane of the material

Question 23

State strain formula and units

Answer 23

𝜀 = ∆𝐿/𝐿

Question 24

Define Young’s Modulus

Answer 24

The ratio of stress to the strain on an object

Question 25

What is Young’s modulus formula?

Answer 25

Young’s modulus (E)=Stress/strain

Question 26

What does the Young’s modulus measure?

Answer 26

The objects stiffness

Question 27

Define elasticity

Answer 27

The property of a body to return to its original state after undergoing a deformation

Question 28

Define plasticity

Answer 28

The property of a body where it undergoes permanent deformation when it is subjected to stress beyond the elastic limit

Question 29

Define fracture point

Answer 29

The maximum strain possible just before the body completely fails

Question 30

Define fracture point

Answer 30

The maximum strain possible just before the body completely feels

Question 31

Define mechanical strength

Answer 31

The level of stress a material under goes to produce a significant change in the state of its structure

Question 32

When is solid is at rest in which direction will it exert its pressure?

Answer 32

It was exit it’s force in the direction of acceleration due gravity

Question 33

Explain the principle of operation of a barometer

Answer 33

The barometer is the device used for measuring atmospheric pressure. It is made up if an evacuated glass tube open that one, and which is inverted in a vessel of mercury. The atmospheric pressure acts on the mercury which forces the mercury up and through the tube. The McCree will continue to rise until the pressure exerted by the mercury in the tube is equal to the atmospheric pressure outside of the tube. The change in the height of the mercury is proportional to the change in atmosphere pressure.

Question 34

What is the equation associated with the barometer?

Answer 34

ℎ ∝ 𝑃𝑎𝑡𝑚

Question 35

Explain the principle of operation of a manometer

Answer 35

Manometer is a device use of measuring pressure and differences of pressure between fluids. It is made up of a glass you bent into a shape containing a liquid, such as mercury. If limb A is connected to a container of gas whose pressure is above atmospheric the pressure of the gas Will cause the levels of the mercury to move, causing a high difference known as h1