Forces And Energy

Question 1

Define a force

Answer 1

A push or pull caused by it interacting with another object

Question 2

What are the contact forces?

Answer 2

• friction
• lift
• thrust
• upthrust
• drag
• NCF
• tension

Question 3

What are the non contact forces?

Answer 3

• weight
• magnetism
• electrostatic

Question 4

What does normal mean

Answer 4

At a right angle

Question 5

What is the unit of force and the symbol for force?

Answer 5

Newton (N)

F

Question 6

What is weight measured in and the symbol for weight

Answer 6

Newtons, N

W

Question 7

What is mass measured in and the symbol for mass?

Answer 7

Kilograms, Kg

m

Question 8

What is gravitational field strength measured in and the symbol for gravitational field strength

Answer 8

Newtons per Kilogram (N/Kg)

g

Question 9

What is the equation for weight?

Answer 9

W = mg

Question 10

What is the difference between something being elastically seformed and inelastically deformed?

Answer 10

• elastically if it goes back to original shape after force is removed
• converse for inelastically

Question 11

What is hooke’s law?

Answer 11

Shows extension of spring, elasticity.

Only true up to limit of proportionality

Question 12

What is the symbol for extension and what is it’s unit?

Answer 12

e

Metres, m

Question 13

What is the symbol for spring constant and its unit?

Answer 13

k

Newtons per meter N/m

Question 14

Define energy

Answer 14

A measure of the ability to do work

Question 15

What does conservation of energy state?

Answer 15

Energy cannot be created or destroyed, only transferred from one store to another

Question 16

What are the 8 energy stores?

Answer 16

Kinetic
Chemical
Thermal
Gravitational potential
Elastic potential
Nuclear
Magnetic
Electrostatic

Question 17

What are the 4 energy pathways?

Answer 17

Can be transferred:

Mechanically
Electrically
By heating
By radiation

Question 18

What is work done?

Answer 18

The energy transferred when a force moves an object through a distance

Question 19

What is the symbol for distance moved and its unit?

Answer 19

s

Metres, m

Question 20

What is the symbol for work done and its unit?

Answer 20

W

Joules, J

Question 21

What is the equation for work done?

Answer 21

W=Fs

Question 22

What is the symbol for energy in the gravitational potential store and its units?

Answer 22

Eg

Joules, J

Question 23

What is the symbol for height and its units?

Answer 23

h

Metres, m

Question 24

What is the equation for energy in the gravitational potential store?

Answer 24

Eg = mgh

Question 25

What is the symbol for energy in the kinetic store and its units?

Answer 25

Ek Joules, J

Question 26

What is the symbol for velocity and its units?

Answer 26

v Metres per second, m/s

Question 27

What is the equation for energy in the kinetic store?

Answer 27

mv² Ek = --------- 2

Question 28

What is the symbol for energy in the elastic potential store and its units?

Answer 28

Ee

Question 29

Equation for energy in the elastic potential store?

Answer 29

ke² Ee = ---- 2

Question 31

What is the symbol for power and its units?

Answer 31

P Watts, W

Question 32

What is the symbol for energy transferred and its units?

Answer 32

E Joules, J

Question 33

What is the symbol for time and its units?

Answer 33

t Seconds, S

Question 34

Equation for power?

Answer 34

E P = -- t

Question 35

What is one watt equivalent to?

Answer 35

One joule per second 1J/s

Question 36

What is useful and wasted energy transfer?

Answer 36

Useful transfer is to the desired store Wasted is transferred to the undesired store

Question 37

What is the equation for efficiency?

Answer 37

Useful energy transf Efficiency= ---------------------------- Total energy input

Question 38

What does a sankey diagram look like?

Answer 38

----------\ ----------/ \ \ \ \ \ \ --- ----- \ / \ / \ ________/

Question 39

How to reduce unwanted energy transfers?

Answer 39

Use insulation (poor heat conductors) Double glazing/cavity walls Lubrication to reduce friction

Question 40

What is conduction?

Answer 40

Energy transfer whereby vibrating particles transfer energy to neighbouring particles Occurs in all states of matter

Question 41

What is covection?

Answer 41

When fluids (liquds and gases) are heated, particles move faster and space between them increases, becoming less dense, so rise to sureface, cool becoming more dense, then sink. This movement is convection

Question 42

What is thermal conductivity?

Answer 42

A measure if the rate a material transfers thermal energy

Question 43

What does non renewable mean?

Answer 43

A resource that is not being replaced as fast as it is being used up, will eventually run out

Question 44

Examples of fossil fuels

Answer 44

Coal, oil, natural gas

Question 45

Advantages of of coal and gas burning power stations?

Answer 45

Very reliable We already have the infrastructure

Question 46

Disadvantages of of coal and gas burning power stations?

Answer 46

Releases CO², a greenhouse gas, causing global warming Non-renewable, will run out

Question 47

Examples of renewable energy

Answer 47

- wind - solar - hydroelectric - tidal - geothermal - biomass - waves

Question 48

Pros and cons of wind energy?

Answer 48

- renewable energy source - doesn't release CO² - flexible location - unreliable, energy production fluctuates with wind speeds

Question 49

Pros and cons of solar energy?

Answer 49

- renewable energy source - doesn't release CO² - flexible location - unreliable due to day-night cycle and weather fluctuations

Question 50

Pros and cons of hydroelectric energy?

Answer 50

- renewable energy source - doesn't release CO² - fixed location - can be unreliable in case of drought