SAGS

Question 1

Vector

Answer 1

A physical quantity that has both magnitude and direction.

Question 2

Scalar quantity

Answer 2

A physical quantity that has magnitude only.

Question 3

Resultant vector

Answer 3

The single vector which has the same effect as the original vectors acting
together.

Question 4

Distance

Answer 4

The length of path travelled (scalar quantity).

Question 5

Displacement

Answer 5

A change in position (vector quantity).

Question 6

Speed

Answer 6

The rate of change of distance (scalar quantity).

Question 7

Velocity

Answer 7

The rate of change of position / The rate of change of displacement / The rate of
displacement (vector quantity).

Question 8

Acceleration

Answer 8

The rate of change of velocity (vector quantity).

Question 9

Weight

Answer 9

The gravitational force the Earth exerts on any object on or near its surface.

Question 10

Normal force

Answer 10

The perpendicular force exerted by a surface on an object in contact with it.

Question 11

Frictional force

Answer 11

The force that opposes the motion of an object.

Question 12

Gravitational field

Answer 12

Description: A region in space where a mass will experience a force.
Def: A force acting per unit mass

Question 13

Newton’s 1st law

Answer 13

An object continues in a state of rest or uniform (moving with constant) velocity
unless it is acted upon by a net or resultant force.

Question 14

Newton’s 2nd law

Answer 14

When a net force, Fnet, is applied to an object of mass, m, it accelerates in the
direction of the net force. The acceleration is directly proportional to the net
force and inversely proportional to the mass.

Question 15

Newton’s 3rd law

Answer 15

When object A exerts a force on object B, object B simultaneously exerts an
oppositely directed force of equal magnitude on object A.

Question 16

Newton’s law of
universal gravitation

Answer 16

Every particle with mass in the universe attracts every other particle with a force
which is directly proportional to the product of their masses and inversely
proportional to the square of the distance between their centres.

Question 17

Gravitational potential
energy

Answer 17

The energy an object possesses due to its position relative to a reference
point.

Question 18

Kinetic energy

Answer 18

The energy an object has as a result of the object’s motion.

Question 19

Mechanical energy

Answer 19

The sum of gravitational potential and kinetic energy at a point.

Question 20

The law of
conservation of
energy

Answer 20

The total energy in a system cannot be created nor destroyed, only transformed
from one form to another.

Question 21

Principle of
conservation of
mechanical energy

Answer 21

In the absence of air resistance or any external forces, the mechanical energy of
an object is constant.

Question 22

Power

Answer 22

The rate at which work is done OR the rate at which energy is transferred.

Question 23

Efficiency

Answer 23

The ratio of output power to input power.

Question 24

Coulomb’s law

Answer 24

Two point charges exert forces on each other. The force is directly proportional
to the product of the charges and inversely proportional to the square of the
distance between the charges.

Question 25

Electric field at a point

Answer 25

The force per unit positive charge

Question 26

Potential difference

Answer 26

The work done per unit positive charge.

Question 27

Current

Answer 27

The rate of flow of charge.

Question 28

Ohm’s law

Answer 28

The current through a conductor is directly proportional to the potential
difference across the conductor at constant temperature.

Question 29

Emf

Answer 29

The total energy supplied per coulomb of charge by the cell.

Question 30

Magnetic flux linkage

Answer 30

The product of the number of turns on the coil and the flux through the coil.

Question 31

Faraday’s law of
electromagnetic
induction

Answer 31

The emf induced is directly proportional to the rate of change of magnetic flux
(flux linkage).

Question 32

Lenz’s law

Answer 32

The induced current flows in a direction so as to set up a magnetic field to
oppose the change in magnetic flux.

Question 33

Inertia

Answer 33

The property of an object that causes it to resist a change in its state of rest or
uniform/constant motion.

Question 34

Work done on an
object by a force

Answer 34

The product of the displacement and the component of the force parallel
to the displacement (scalar quantity).

Question 35

Linear momentum

Answer 35

The product of the mass and velocity of the object (vector quantity).

Question 36

Newton’s 2nd law in
terms of momentum

Answer 36

The net force acting on an object is equal to the rate of change of momentum.

Question 37

Law of conservation
of linear momentum

Answer 37

The total linear momentum of an isolated system remains constant.

Question 38

Elastic collision

Answer 38

A collision in which both momentum and kinetic energy are conserved.

Question 39

Inelastic collision

Answer 39

A collision in which only momentum is conserved.

Question 40

Impulse (J)

Answer 40

The product of the net force and the contact time.

Question 40

Work – energy
theorem

Answer 40

The work done by a net force on an object is equal to the change in the kinetic
energy of the object.

Question 41

Diode

Answer 41

A component that only allows current to flow in one direction.

Question 42

Photoelectric effect

Answer 42

The process that occurs when light shines on a metal and electrons are ejected.

Question 43

Threshold frequency
(cut-off frequency)

Answer 43

The minimum frequency of incident radiation at which electrons will be emitted
from a particular metal.

Question 44

Work function

Answer 44

The minimum amount of energy needed to emit an electron from the surface of
a metal (material specific).