SP3

Question 1

define Energy and its unit

Answer 1

the ability to do work, unit of energy is joules

Question 2

Types of Energy

Answer 2

1. Chemical Energy
2. Thermal Energy
3. Kinetic Energy
4. Gravitational Potential Energy
   5.Elastic Potential Energy
   6.Sound Energy
   7.Light Energy

Question 3

Ways in which energy can be transferred

Answer 3

1. By a force
2. by heating
3. by light or sound
4. by electricity (electric currents)

Question 4

describe the law of conservation of energy

Answer 4

-energy is neither created nor destroyed. it can only be transferred from one store to another

Question 5

describe energy transfer in car breaking

Answer 5

-kinetic energy stored in a moving car
-transferred by forces during breaking
-thermal energy in car breaks

Question 6

What is effciency

Answer 6

A way of describing how good a machine is at transferring energy into useful forms

Question 7

efficiency calculation

Answer 7

useful energy output(J) / total energy output J)

Question 8

What can reduce friction?

Answer 8

Lubrication in the form of Oil or other fluids(a liquid/gas)

Question 9

Ways in which heat energy can be transferred? And their definitions

Answer 9

1. Conduction
2. Convection
3. Radiation
4. conduction is the transfer of heat energy through direct contact
5. convection is the transfer of heat enerfy through the movement of a fluid(liqud/gas)
6. radiation is the transfer of thermal energy through thermal emissions

Question 10

Describe Convection Current

Answer 10

When hot air rides and cold air rises

(air can be replaced by any fluid)

Question 11

Best emitter/Absorber of heat

Answer 11

dull black

Question 12

Best insulator

Answer 12

Shiny Metal

Question 13

Describe Thermal Conductivity and Low thermal Conductivity

Answer 13

Thermal Conductivity: Ability of the material to transfer heat

Low thermal Conductivity: when energy is not transferred through them very easily by heating

Question 14

Arrangement of particles in Insulators

Answer 14

Large spaces between particles which makes it harder for vibrations to pass from one particle to another. This means heat energy does not pass easily through insulators

Question 15

What is Gravitational Potential Energy and its formula?

Answer 15

GPE is the energy stored in an object due to its position above the earth’s surface

GPE = m(kg) x g(usually 10) x h(m)

Question 16

Kinetic Energy Formula

Answer 16

1/2 x m(kg) x (v(m/s) )^2

Question 17

Describe Non renewable resources and list a few

Answer 17

An energy source that eventually will run out and cannot be used again.

Can be classed into
1. Fossil fuels(oil, coal, natural gas)
2. Nuclear Fuel (Uranium)

Question 18

Types of renewable energy

Answer 18

1. solar energy
2. wind energy
3. hydroelectric power energy
4. tidal energy
5. bio energy
6. geothermal energy