Forces In Action ch. 8

Question 1

Contact Force

Answer 1

When one object comes in contact with another object
Eg.
1.Brushing your hair
2. Hitting a gold ball

Question 2

No Contact Force

Answer 2

The motion and shape of objects can be changed without touching them with anything
Eg.
1. When you drop a tennis ball, it speeds up as it falls through the air.

Question 3

Gravity

Answer 3

• The Force of gravity pulls down
• Gravity is a non-contact force
• Other types of Non-contact force involve magnetic force and electro static force

Question 4

Force

Answer 4

A Force is a push or pull in a particular direction
(They are occurring around us all the time)
1. Pull the door open
2. Pushing a couch
3. The force you use to push the pen open and close

Question 5

Permanent Magnets

Answer 5

Permanent Magnets are magnets that retain their magnetism when removed from other magnets

Question 6

Temporary Magnets

Answer 6

Temporary Magnets are magnets that loose their magnetism when removed from another magnet.

Question 7

Attraction

Answer 7

The force by which one object attracts another

Question 8

Repulsion

Answer 8

An opposing force

Question 9

Magnetic fields

Answer 9

Magnetic fields are the areas where the magnetic force acts

Question 10

Domains

Answer 10

Domains are little compartments in an object that make thr object magnetic

Question 11

Electromagnet

Answer 11

An electromagnet is a coil of wire wrapped around an iron coil

Question 12

Nucleas

Answer 12

roundish structure inside cells that acts as the control centre for the cell. Plural = nuclei

Question 13

Electrons

Answer 13

Very light, negatively charged particles inside an atom. Electrons move around the central nucleus of an atom

Question 14

Protons

Answer 14

tiny, but heavy, particle found in the nucleus of an atom. Protons have a positive electrical charge

Question 15

Positive electric charge

Answer 15

the charge on an atom or object with fewer electrons than protons

Question 16

Neutrons

Answer 16

tiny, but heavy, particles found in the nucleus of an atom. Neutrons have no electrical charge

Question 17

Neutral

Answer 17

having the same number of protons and electrons

Question 18

Static electricity

Answer 18

a build-up of charge in one place

Question 19

Insulators

Answer 19

materials that do not allow electric charge to flow through them

Question 20

Conductors

Answer 20

materials that allow electric charge to flow through them

Question 21

Lightning rods

Answer 21

conductive metal rod, often attached to the top of tall buildings. Lightning rods help to keep buildings safe from lightning strikes

Question 22

Mass

Answer 22

a measure of the amount of material in an object of substance

Question 23

Weight

Answer 23

a measure of the size of the gravity force pulling an object towards the centre of a massive body, such as the Earth. The weight of an object depends on the object’s mass

Question 24

Newton

Answer 24

the unit for measuring forces

Question 25

Air resistance

Answer 25

the force of air pushing on an object as the object moves through the air

Question 26

Terminal speed

Answer 26

the constant speed reached by a falling body. A body reaches terminal speed when the force of gravity pulling it down is balanced by the air resistance pushing against it

Question 27

Friction

Answer 27

a force that acts against the movement of an object. It occurs between any surfaces that are touching and trying to move past each other

Question 28

Traction

Answer 28

type of friction used to assist movement

Question 29

Lubricants

Answer 29

Substance with large particles that can slide easily over each other. Lubricants are used between surfaces that rub against each other to reduce wear and increase motion between the surfaces

Question 30

Fluid

Answer 30

a substance that flows and has no fixed shape. Gases and liquids are fluids

Question 31

Streamlined

Answer 31

Shaped so that drag through a fluid is minimised

Question 32

Mass

Answer 32

a measure of the amount of material in an object of substance

Question 33

Weight

Answer 33

a measure of the size of the gravity force pulling an object towards the centre of a massive body, such as the Earth. The weight of an object depends on the object’s mass

Question 34

Newton

Answer 34

the unit for measuring forces

Question 35

Air resistance

Answer 35

the force of air pushing on an object as the object moves through the air

Question 36

Terminal speed

Answer 36

the constant speed reached by a falling body. A body reaches terminal speed when the force of gravity pulling it down is balanced by the air resistance pushing against it

Question 37

Friction

Answer 37

a force that acts against the movement of an object. It occurs between any surfaces that are touching and trying to move past each other

Question 38

Traction

Answer 38

type of friction used to assist movement

Question 39

Lubricants

Answer 39

Substance with large particles that can slide easily over each other. Lubricants are used between surfaces that rub against each other to reduce wear and increase motion between the surfaces

Question 40

Fluid

Answer 40

a substance that flows and has no fixed shape. Gases and liquids are fluids

Question 41

Streamlined

Answer 41

Shaped so that drag through a fluid is minimised

Question 42

Buoyancy

Answer 42

a force which keeps objects floating

Question 43

Surface tension

Answer 43

the ‘firmness’ of the surface of a liquid created by the attraction between particles at the surface. The surface acts like an elastic skin