Chapter 1: Application of Forces and Transfer of Energy

Question 1

What is a Force?

Answer 1

A “push” or a “pull”.

Question 2

What are the 2 types of forces?

Answer 2

Contact forces, and non-contact forces.

Question 3

What is Frictional force?

Answer 3

Frictional force is the contact force that acts on two materials rubbing against each other.

Question 4

What Is Gravitational force?

Answer 4

gravitational force is the non-contact force that attracts object to huge masses. (the force of gravity is called weight!)

Question 5

How do like and unlike charges/poles interact?

Answer 5

Like charges repel each other. Unlike charges attract each other.

Question 6

What is mass and what is its S.I. unit?

Answer 6

Mass is a measure of the quantity of matter in a body. The S.I. unit is Kilograms (Kg)

Question 7

What is weight and what is its S.I. unit?

Answer 7

The amount of force acting on an object due to gravity. The S.I. unit is Newtons (N)

Question 8

What does a spring balance measure? What does a electronic balance measure?

Answer 8

A spring balance measures force/weight and then electronic balance measures mass.

Question 9

What are the effects of forces?

Answer 9

1. Changes size and shape
2. Move a stationary object
3. Change direction of moving objct
4. Change speed of moving object
5. Stop moving object

Question 10

What is the definition of speed and what is its S.I. unit?

Answer 10

Speed is the distance travelled per unit time and its S.I. unit is m/s.

Question 11

What is the formula to calculate speed?

Answer 11

Distance travelled / time taken

Question 12

What is a turning effect?

Answer 12

when a force is applied onto an object with a pivot, it creates a turning effect, causing the object to turn around the pivot

Question 13

What is the formula for calculating moment and its unit?

Answer 13

moment = force * perpendicular distance of force to pivot. Moment = Nm

Question 14

What is the definition of pressure and what is its units?

Answer 14

pressure is caused by a force being exerted on a surface. It can also be the amount of force acting perpendicularly on a unit area.

Question 15

What is the formula to calculate pressure?

Answer 15

Pressure = force / contact area

Question 16

What happens when there are regions of pressure difference?

Answer 16

The region with a higher pressure will exert a force towards the region with the lower pressure.

Question 17

What is pressure in liquids and how does it change?

Answer 17

when an object is immersed in a body of liquid, the liquid exerts pressure on it. The deeper an object is immersed, the greater the liquid pressure is.

Question 18

What is the formula to calculate weight?

Answer 18

Weight = mass * gravity acting onto object

Question 19

What is energy and what is its S.I. Unit?

Answer 19

Energy is the ability to do work. Its S.I. Unit is joules ( J )

Question 20

What are the main types of energy?

Answer 20

Kinetic energy, electrical energy, thermal energy, light energy, sound energy, gravitational potential energy, chemical potential energy, elastic potential energy.

Question 21

What is the formula to calculate work done?

Answer 21

Work done = force * distance moved in direction of force

Question 22

What is the principle of conservation of energy?

Answer 22

Energy cannot be created or destroyed. it can only be converted from one form to another.

Question 23

What are the 2 sources of energy?

Answer 23

renewable, and non-renewable

Question 24

What are the renewable sources of energy?

Answer 24

biofuels, solar, geothermal, hydroelectric, and wind.

Question 25

What are the non-renewable sources of energy?

Answer 25

Fossil fuels

Question 26

What are the three types of fossil fuels?

Answer 26

Crude oil, natural gas and coal.

Question 27

How do fossil fuel work?

Answer 27

The fuel is burnt, which releases heat. The heat boils water, and the steam that comes from it turns a turbine, which then turns a generator that generates electricity.

Question 28

What is the consequence of using fossil fuels?

Answer 28

When fossil fuels are burnt, massive amount of carbon dioxide is produced and released into the atmosphere. This traps heat from the sun in the earths atmosphere, causing global warming. Global warming causes temperatures around the world to rise and causes erratic and destructive weather patterns.

Question 29

Where are biofuels derived from?

Answer 29

They are derived from animal and plant matter.

Question 30

What is the energy conversion for fossil fuel?

Answer 30

Chemical potential energy -> thermal energy -> kinetic energy -> electrical energy

Question 31

What is the energy conversion for biofuels?

Answer 31

Chemical potential energy -> thermal energy -> kinetic energy -> electrical energy

Question 32

What is geothermal energy derived from?

Answer 32

It is derived from hot rocks, deep underground in volcanic areas.

Question 33

What is the energy conversion in geothermal power stations?

Answer 33

Thermal energy -> Kinetic energy -> electrical energy

Question 34

What is a disadvantage of geothermal energy?

Answer 34

Some power stations extract poisonous substances, such as hydrogen sulfide arsenic from deep underground. The land around geothermal power stations may sink during extraction or building of underground water pipes.

Question 35

What is the energy conversion in hydroelectric power stations?

Answer 35

Gravitational potential energy -> kinetic energy -> electrical energy

Question 36

What are the disadvantages of hydroelectric power stations?

Answer 36

In places where hydroelectric dams are built, the ecosystems around it are affected in ways like extensive flooding in forests, causing damage to natural wildlife habitats, as well as preventing the flow of sediments and nutrients down rivers.

Question 37

What is the energy conversion in solar cells?

Answer 37

Light energy -> electrical energy

Question 38

What are the advantages and disadvantages of using solar energy?

Answer 38

Solar energy does not produce any pollutants. However, it is an expensive technology which is not very affordable for everyone.

Question 39

What is the energy conversion when using wind, and wind turbines for energy?

Answer 39

Kinetic energy -> electrical energy

Question 40

What are the disadvantages to using wind, and wind turbines for energy?

Answer 40

These areas require huge empty fields, and the rotating wind turbines produce a low frequency noise that cause people to experience, headaches, and to feel nauseous.

Question 41

What is Magnetic force?

Answer 41

Magnetic force is the non-contact force exerted by a magnet on magnetic materials such as iron steel, cobalt and nickel.

Question 42

What is electrostatic force?

Answer 42

Electrostatic forces are attractive or repulsive forces between particles that are caused by their electric charges.