Mechanics

Question 1

Vector

Answer 1

A quantity which has magnitude and direction

Question 2

Scalar

Answer 2

A quantity which has magnitude only

Question 3

Distance

Answer 3

A measure of the separation between two points

Question 4

Displacement

Answer 4

The separation between two points in a given direction

Question 5

Speed

Answer 5

The distance travelled per unit time

Question 6

Velocity

Answer 6

The rate of change of the displacement

Question 7

Acceleration

Answer 7

The rate of change of the velocity

Question 8

Momentum

Answer 8

The product of the mass and velocity of a body

Question 9

The principle of conservation of momentum

Answer 9

In any closed system of colliding bodies, the total momentum remains constant

Question 10

Force

Answer 10

That which can cause acceleration

Question 11

Newton

Answer 11

A force of one Newton gives a mass of one kg and acceleration of 1 m/s2

Question 12

Weight

Answer 12

A force equal to the product of mass and acceleration due to gravity

Question 13

Friction

Answer 13

The force that opposes motion between two surfaces in contact

Question 14

Newton’s First law of motion

Answer 14

A body remains at rest or a uniform motion unless acted on by a resultant force

Question 15

Newton’s second law of motion

Answer 15

The rate of change of momentum is directly proportional to the applied force and takes place in the same direction in which the force acts
F = ma

Question 16

Newton’s third law of motion

Answer 16

For every action there is an equal and opposite reaction

Question 17

Work

Answer 17

Done when a force causes a body to be displaced
W = Fd

Question 18

Energy

Answer 18

The ability to do work

Question 19

1 Joule

Answer 19

The work done when a force of 1 N this place is an object by 1 m

Question 20

The principle of conservation of energy

Answer 20

States that energy can neither be created nor destroyed, but can change from one form to another

Question 21

Power

Answer 21

The race at which work is done for energy is converted P = W/t

Question 22

1 Watt

Answer 22

The race of doing work equal to 1 joule per second

Question 23

Potential energy

Answer 23

The energy a body has due to its position or state

Question 24

Kinetic energy

Answer 24

The energy a body has due to its motion

Question 25

Renewable source of energy

Answer 25

One that will not be exhausted e.g. wind tidal and solar. A non-renewable source will eventually run out; coal oil natural gas

Question 26

Efficiency of machine

Answer 26

Useful energy output as a percentage of energy input

Question 27

Lever

Answer 27

Any rigid body that is free to rotate about a fixed point called a fulcrum

Question 28

The centre of gravity

Answer 28

The point of an object through which the weight of the object appears to act

Question 29

The moment of a force (torque)

Answer 29

The force applied multiplied by the perpendicular distance to the fulcrum M =Fd

Question 30

Conditions for equilibrium

Answer 30

1. The vector sum of the forces in any direction must be zero 2. The sum of the moments about any point must be zero

Question 31

Couple

Answer 31

2 equal parallel forces that act in opposite directions

Question 32

Moment of a couple

Answer 32

The magnitude of one force multiplied by the perpendicular distance between the two forces

Question 33

Hooke's law

Answer 33

In an elastic body the restoring force is proportionately the displacement of the stretched object from its equilibrium position F = -ks

Question 34

Simple harmonic motion

Answer 34

The acceleration of a body towards its mean position is directly proportional to its distance from that position and always directed towards it A = - ω s

Question 35

Newton's law of universal gravitation

Answer 35

The force between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between the

Question 36

Centripetal Force

Answer 36

The force required to maintain uniform circular motion. It is directed towards the center of the circle

Question 37

Centripetal acceleration

Answer 37

The acceleration of an object to traveling in uniforms circular motion. It is directed towards the center of the circle

Question 38

Angular velocity

Answer 38

The rate of change of an angle

Question 39

Angle

Answer 39

Measured ingredients is equal to the arc length divided by the radius

Question 40

Elastic constant

Answer 40

The constant of proportionality between the applied force and the resulting displacement of a given spring

Question 41

Elasticity

Answer 41

The ability of a body to resist a distorting influence or stress and to return to its original size and shape when the stress is removed

Question 42

Periodic time

Answer 42

The time taken to complete one revolution

Question 43

Kepler's third law

Answer 43

The square of the periodic time of a satellite is directly proportional to the cube of its radius of orbit and inversely proportional to the mass of the planet in orbits

Question 44

Density

Answer 44

The mass per unit volume of a substance p=m/V

Question 45

Pressure

Answer 45

The force per unit area P = F/A

Question 46

Archimedes principle

Answer 46

When a body is partially or fully immersed in a fluid, it experiences an uptrust which is equal to the weight of fluid displaced

Question 47

Law of flotation

Answer 47

A floating body displaces his own ways of fluid

Question 48

Boyles law

Answer 48

For a fixed mass of gas at constant temperature its volume is inversely proportional to its pressure

Question 49

Acceleration due to gravity

Answer 49

The acceleration experienced by a body in free fall within the gravitational field of a massive body