Defintions

Question 1

Impulse

Answer 1

Change in momentum

Question 2

Circular motion

Answer 2

• Motion I which the the velocity, and therefore momentum, is always changing
• Resultant force and acceleration act perpendicularly to the direction of motion, towards the centre

Question 3

Radian

Answer 3

The angle subtended by a circle of radius r, with arc length r

Question 4

Angular speed

Answer 4

The angle an object moves through per second

Question 5

Simple harmonic motion

Answer 5

Motion where acceleration is directly proportional to displacement, but acceleration and displacement act in opposite directions

Question 6

Period

Answer 6

Time for one oscillation

Question 7

Frequency

Answer 7

Oscillations per second

Question 8

Damping

Answer 8

Change in amplitude due to force that causes an oscillating object to lose energy

Question 9

Damped oscillation

Answer 9

Oscillations in a system decreasing in amplitude because of a force opposing motion and causing the oscillating object to lose energy. Acts oppositely to velocity

Question 10

Mechanical energy

Answer 10

Sum of potential and kinetic energy in an oscillating system

Question 11

Critical damping

Answer 11

Damping that causes the amplitude to reduce to zero in he shortest possible time

Question 12

Over damping

Answer 12

Heavy damping that takes a longer time than critical damping to reach an amplitude of zero

Question 13

Resonance

Answer 13

When the frequency of the applied force is equal to the natural frequency of the system and it oscillates with maximum amplitude

Question 14

Driving frequency

Answer 14

Frequency of external force applied

Question 15

Natural frequency

Answer 15

Frequency of free oscillations of an oscillating system

Question 16

Resonant frequency

Answer 16

The frequency at which the amplitude is at its maximum

Question 17

Conservation of momentum

Answer 17

In any collision or explosion, the total momentum remains constant in the system, provided no external force acts on the system

Question 18

Gravitational field

Answer 18

A region in which a mass experiences a force

Question 19

Gravitational field strength

Answer 19

The force acting per unit mass

Question 20

Newtons law of gravitation

Answer 20

• Force is proportional to the products of the two masses

* Inversely proportional to the distance between the two squared

Question 21

Gravitational potential

Answer 21

Work done per unit mass to move a mass from infinity to a known point in the field

Question 22

Gravitational potential gradient

Answer 22

Change in gravitational potential over a distance

Question 23

Equipotential

Answer 23

Lines of constant potential

Question 24

Geosynchronous satellite

Answer 24

A satellite orbiting exactly above the equator with a period of 24 hours

Question 25

Orbital period

Answer 25

The time it takes for the satellite to make one complete orbit around a mass

Question 26

Electric field

Answer 26

Region where a charged particle experiences a force

Question 27

Electric field strength

Answer 27

The force per unit charge of a positive test charge

Question 28

Coulomb's law

Answer 28

* Force between two charged particles is proportional to product of charges * Inversely proportional to the distance between them squared

Question 29

Electric potential

Answer 29

The work done per unit charge on a small positive test charge when moving the charge from infinity to a point

Question 30

Dielectric

Answer 30

Two electrical conducting plates, separated by an electrical conductor

Question 31

Time constant

Answer 31

The time taken for the charge to drop to 1/e percent of its original value (around 63 percent)

Question 32

Magnetic field

Answer 32

A region which a magnetic force acts on a charged body or magnetically susceptible materials

Question 33

Motor effect

Answer 33

The force on a current carrying conductor due to a magnetic field

Question 34

Electromagnetic induction

Answer 34

The generation of an emf when the magnetic flux linkage through a coil changes or when a conductor cuts magnetic field lines

Question 35

Back emf

Answer 35

Emf induced in a spinning coil or an electric motor or in any coil in which the current is changing. The back end acts against the potential difference

Question 36

Magnetic flux

Answer 36

The product of the magnetic flux density and the area it is covering

Question 37

Flux linkage

Answer 37

The product of the magnetic flux and the and the number of coil turns cutting the field

Question 38

Faradays law

Answer 38

The induced emf is directly proportional to the rate of change of flux linkage

Question 39

Lenz's law

Answer 39

The induced emf is always in such a direction that opposes the the change that causes it

Question 40

Transformer

Answer 40

Something that converts the amplitude of an alternating potential difference to a different value

Question 41

Eddy currents

Answer 41

Unwanted induced currents in the metal parts of transformers