Chapter 8-Forces In Action

Question 1

Force

Answer 1

a push, pull or twist. Forces are measured in newtons (N). (verb) to push, pull or twist

Question 2

Contact Forces

Answer 2

A force of that acts only between objects that are touching

Question 3

Gravity

Answer 3

The force of attraction that exists between any two bodies in the universe that have mass. The gravity at the Earth’s surface is the pull on objects near its surface towards the centre of the Earth

Question 4

Non-contact force

Answer 4

A force that acts between objects are not touching

Question 5

Magnetic Forces

Answer 5

The force of electric charges at rest. We experience electrostatic forces when we pull off a jumper and our hair stands on end

Question 6

Permanent Magnets

Answer 6

A magnet that retains its magnetic effect for many years

Question 7

Alloys

Answer 7

A mixture of non metal with a metal or another metal

Question 8

Temporary Magnets

Answer 8

A magnet that stays magnetic only while it touches a permanent magnet, or one that is magnetic for a very short time.

Question 9

North Pole

Answer 9

The end of the magnet that, when free to rotate, points to the North pole of the Earth. The poles of the Earth are the points where the axis of the Earth Surface

Question 10

South Pole

Answer 10

The end of the magnet that, when free to rotate, points to the South Pole of the Earth. The poles of the Earth are the points where the axis of the Earth’s rotation meets the Earth’s surface.

Question 11

Repulsion

Answer 11

An opposing force

Question 12

Domains

Answer 12

The three domains of classification are Archaea, Bacteria and Eukarya

Question 13

Magnetic Field

Answer 13

A map of the lines showing the size and direction of a magnetic force. The size of the force is shown by how close together the lines are. The direction at any point is given by the direction in which the north pole of a magnet would face

Question 14

Electromagnets

Answer 14

Electromagnets are produced when electricity is used to produce a temporary magnet. A simple electromagnet is made by winding an electrical electromagnet is made by winding an electrical cable around an iron nail and then passing an electric current through the cable. The iron nail becomes a magnet only while the electricity flows.

Question 15

Atoms

Answer 15

A very small particle that makes up all things. Atoms have the same properties as the objects they make up.

Question 16

Nucleus

Answer 16

Roundish structure inside cells that acts as the control centre for the cell

Question 17

Electrons

Answer 17

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

Question 18

Negative Electric charge

Answer 18

The charge of an atom or object with fewer electrons than protons

Question 19

Protons

Answer 19

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

Question 20

Positive electrical charge

Answer 20

The charge of an atom or object with fewer electrons than protons

Question 21

Neutrons

Answer 21

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

Question 22

Static Electricity

Answer 22

A build up charge in one place

Question 23

Insulators

Answer 23

Materials that do not allow electric charge to flow through them

Question 24

Mass

Answer 24

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

Question 25

Weight

Answer 25

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 26

Newton

Answer 26

The unit for measuring forces

Question 27

Air resistance

Answer 27

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

Question 28

Terminal Speed

Answer 28

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 29

Friction

Answer 29

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 30

Traction

Answer 30

A type of friction used to assist movement