Definitions

Question 1

MASS

Answer 1

The quantity of matter contained within a body.

Symbol: m
Unit: kg

Question 2

WEIGHT

Answer 2

The force of attraction of gravity on a given mass.

Formula: W = mg
Unit: Newton

Question 3

DISTANCE

Answer 3

The interval between 2 points, not in a straight line.

Symbol: d
SI Unit: metre (m)

Question 4

DISPLACEMENT

Answer 4

The linear distance between 2 defined points.

Symbol: s
SI Unit: metre (m)

Question 5

SCALAR

Answer 5

Sufficiently defined when magnitude only is given in the appropriate units.

E.g. distance

Question 6

VECTOR

Answer 6

Requires direction to be stated in order to completely define it.

E.g. velocity - as it has magnitude.
Direction - metres per a second.

Question 7

SPEED

Answer 7

The rate of change of distance with time.

Symbol: U & V
Units: m/s

Question 8

VELOCITY

Answer 8

The rate of change of displacement with time. (Speed with a specific direction is a velocity)

Symbol: U & V
Units: m/s

Question 9

ACCELERATION

Answer 9

The rate of change of velocity with time.

Symbol: a
SI Units: m/s^2

Question 10

FORCE

Answer 10

An external agency capable of altering the state of rest or uniform motion of a body.

The force , F, required to produce an acceleration, a, in a mass, m, is given by: F=ma

Symbol: N
SI Unit: Newton

Question 11

NEWTON

Answer 11

The force requires to give a mass of 1 kilogram an acceleration of 1 metre per a second.

A Newton is a unit of force, reoriented by the symbol N.

Question 12

CENTRIPETAL ACCELERATION

Answer 12

The acceleration of a body travelling in a curved path that is directed towards the centre of the curve or axis of rotation.

The magnitude of centripetal acceleration is given by the equation: a= v^2 / r

Question 13

CENTRIPETAL FORCE

Answer 13

The external force required to make a body follow a curved path.

The magnitude of the centripetal force is given by the equation:

Fc = mv^2 / r

Question 14

CRITICAL SPEED

Answer 14

The maximum speed in which a body can travel in a curved as limited by the centripetal acceleration.

Question 15

GRAVITATIONAL FORCE

Answer 15

The force of attraction between all objects that tends to pull them towards one another.

Symbol: g
Units: m/s^2
Value: 9.81 m/s^2

Question 16

CENTRE OF GRAVITY

Answer 16

The fixed point through which the resultant force of gravity always passes, irrespective of the position of the body.

Question 17

INERTIA

Answer 17

The property of matter that causes it to resist any change of its motion in either direction or speed.

Question 18

FRICTION

Answer 18

The force that opposes the relative motion or tendency to such motion of 2 surfaces in contact.

Question 19

COEFFICIENT OF SLIDING FRICTION

Answer 19

The ratio between the force required to keep a body in uniform motion over a surface and the weight of that body.

Represented by μ (mu)

μ = force / weight

Question 20

DYNAMICS

Answer 20

The branch of mechanics concerned with the motion of bodies under the attraction of force.

Question 21

MOMENTUM

Answer 21

The momentum of an object is defined as the product of a mass and its velocity.

Symbol: p
Equation: p = mv

Question 22

INERTIAL FRAME OF REFERENCE

Answer 22

A frame of reference that is not accelerating or rotating.

Question 23

NEWTONS 1st LAW OF MOTION

Answer 23

A body in motion remains in motion or a body in rest remains at rest, unless acted on by another force.

Question 24

NEWTONS 2nd LAW OF MOTION

Answer 24

The rate of change of momentum is proportional to the applied force and takes place on the direction of the applied force.

Force equals mass times acceleration.
F = ma

Question 25

NEWTONS 3rd LAW OF MOTION

Answer 25

For every action, there is an equal and opposite reaction.