Definitions

Question 1

Scalar

Answer 1

Quantity defined by a magnitude and unit

Question 2

Vector

Answer 2

Quantity defined by magnitude, unit and direction

Question 3

Moment

Answer 3

Product of force and its perpendicular distance to a pivot

Question 4

Centre of mass / gravity

Answer 4

The point where the entire mass / gravity of an object seems to act

Question 5

Principle of moments

Answer 5

For a system in rotational equilibrium, the summation of the clockwise moments about a point is equal to the summation of the anticlockwise moments about the same point

Question 6

Velocity

Answer 6

Rate of change of displacement

Question 7

Acceleration

Answer 7

Rate of change of velocity

Question 8

Projectile motion

Answer 8

Uniform velocity in one direction and uniform acceleration in a perpendicular direction

Question 9

Newton’s 1st law

Answer 9

A body will continue in a state of rest or constant velocity unless acted on by a resultant force

Question 10

Newton’s 2nd law

Answer 10

A body subject to a resultant force will accelerate in the same direction as the resultant force
Fr = ma
Acceleration is directly proportional to fr but inversely proportional to m

Question 11

Newton’s 3rd law

Answer 11

If body A exerts a force on body B, body B will exert a force that is equal in magnitude but in the opposite direction to body A

Question 12

Momentum

Answer 12

Product of a body’s mass and velocity
p = mv

Question 13

Principle of conservation of linear momentum

Answer 13

For a closed system, the total momentum before a collision = total momentum after the collision.

Question 14

Elastic collision

Answer 14

Ke is conserved, total energy is constant

Question 15

Inelastic collision

Answer 15

Ke isn’t conserved, total energy is constant

Question 16

Totally inelastic collisions

Answer 16

2 objects stick together with a large loss in ke, total energy is constant

Question 17

Impulse

Answer 17

Product of force and time the force is applied for.
f x t

Question 18

Newton’s 2nd law in terms of momentum

Answer 18

Rate of change of momentum of a body is proportional to the applied force and acts in the same direction as the force

Question 19

Electric current

Answer 19

Rate of flow of charge

Question 20

What is Potential difference across a component defined as

Answer 20

Amount of electrical energy transferred to other forms when unit charge passes through the component

Question 21

Electromotive force

Answer 21

Amount of electrical energy produced from other forms when unit charge passes through a power source

Question 22

Volt

Answer 22

1 joule of energy dissipated /unit charge

Question 23

4 conditions required for a couple

Answer 23

Forces are…
Acting in opposite directions
Aren’t along the same straight line
Same size
Parallel

Question 24

Resistivity

Answer 24

The resistance of 1m of material of cross sectional area m^2

Question 25

Superconductor

Answer 25

A material which loses all its electrical resistivity to become a perfect conductor when it is below its critical (or transition) temperature

Question 26

Ohm’s law

Answer 26

Potential difference is directly proportional to the current through it, provided the temperature remains constant

Question 27

Lost volts

Answer 27

The energy dissipated per unit charge within a cell/power source due to its internal resistance

Question 28

Work done

Answer 28

Product of force and distance moved in the direction of the force

Question 29

Potential energy

Answer 29

Stored energy (GPE)

Question 30

Kinetic energy

Answer 30

Movement energy

Question 31

Displacement

Answer 31

Change in position of object

Question 32

Average velocity

Answer 32

Change in displacement divided by time taken

Question 33

Potential divider (what it does and some real world examples)

Answer 33

Provides variable supply of pd to a circut with a fixed power supply

Lighting /Heating circuits

Question 34

Kirchhoff’s law

Answer 34

Charge entering a junction = charge leaving junction