Week 1

Question 1

What is the formula for kinetic energy? (symbols and what they are measured in).

Answer 1

Ek = 1/2M x V2

Joules Kg m/s

Question 2

What is the formula for gravitational potential energy? (symbols and what they are measured in).

Answer 2

Ep = M x G x H

Joules Kg N/kg M

Question 3

What is the formula for elastic potential energy? (symbols and what they are measured in).

Answer 3

Ee = 1/2 K x e2
Joules spring constant(stiffness)N/m extension(how
far it has extended)

Question 4

What is the rule about energy in a closed system?

Answer 4

Energy cannot be created or destroyed, only transferred.

Question 5

What is the equation for power?

Answer 5

Power = Energy/Time

Watts Joules Seconds

Question 6

What is convection?

Answer 6

Convection can happen in liquids and gases, when air is heated it rises and its density decreases. Because liquids and gases can flow, the warmer areas rise above the colder areas. If there is a constant heat source, a convection current has been formed.

Question 7

What is specific heat capacity?

Answer 7

The amount of energy needed to raise the temperature of 1kg of a substance by 1 degree Celsius.

Question 8

What is the equation for specific heat capacity?

Answer 8

Energy = Mass x specific heat capacity x change in temperature
E m c Theta
Energy = Joules
mass = Kg
Specific heat capacity = J/Kg°C
Change in temperature = °C

Question 9

How do you reduce unwanted energy transfers?

Answer 9

Lubrication
Home insulation
Streamlining

Question 10

How do you reduce energy transfer in homes?

Answer 10

• Loft insulation
• Cavity wall insulation
• Double glazing
• Draught excluders
• Thicker walls
• Walls with low thermal conductivity

Question 11

What is the formula for efficiency?

Answer 11

Efficiency = Useful power output/total power input

Question 12

Examples of non-renewable energy resources?

Answer 12

• Coal
• Oil
• Gas
• Nuclear

Question 13

Examples of renewable energy resources?

Answer 13

• Solar
• Wind
• Water waves
• Hydro-electricity
• Bio-fuel
• Tides
• Geothermal

Question 14

What are energy resources used for?

Answer 14

• Heating
• Transport
• Generating electricity

Question 15

What is current?

Answer 15

The rate of flow of charge (electrons)

Question 16

What is the unit for current?

Answer 16

Amps

Question 17

What is the unit for resistance?

Answer 17

Ohms

Question 18

What is the equation for charge?

Answer 18

Q = I x T

Q = Charge flow - Coulombs
I = Current - Amps
T = Time - seconds

Question 19

What is the equation for potential difference?

Answer 19

V = I x R

V = Voltage - Volts
I = Current - Amps
R = Resistance - Ohms

Question 20

What is the practical for investigating resistance?

Answer 20

• Attach a crocodile clip at 0 cm.
• 2nd crocodile clip at 10 cm.
• Record the current ant the voltage.
• Move 2nd crocodile clip another to 20 cm
• Record current and voltage
• Repeat for different lengths
• Then use the V = I x R to figure out the resistance

Question 21

What are the rules in series circuits?

Answer 21

• Current is the same at any point
• Voltage is shared between components (components with bigger resistance have bigger share of pd)
• Total resistance is the sum of the individual resistors