Mechanics

Question 1

Physical Quantity

Answer 1

One that can be measured, calculated and expressed in numbers

Question 2

Scalar Quantity

Answer 2

One with magnitude only. It has no directional component.

Question 3

Distance

Answer 3

Measure of how far one point is from the other.

Question 4

Time

Answer 4

Used to measure the duration of events, to put them in sequence or to measure the interval between them.

Question 5

Speed

Answer 5

Distance travelled per unit time.

Question 6

Vector Quantity

Answer 6

One with both magnitude and direction.

Question 7

Displacement

Answer 7

Distance in a given direction.

Question 8

Velocity

Answer 8

Rate of change of displacement with respect to time.

Question 9

Acceleration

Answer 9

Rate of change of velocity with respect to time.

Question 10

Mass

Answer 10

Measure of the amount of matter in a body.

Question 11

Momentum

Answer 11

Product of mass and velocity.

Question 12

Acceleration due to gravity

Answer 12

Acceleration experienced by a body in free fall within the gravitational field of a massive body.

Question 13

Weight

Answer 13

Force equal to the product of mass and acceleration due to the gravity.

Question 14

Centre of Gravity

Answer 14

Point at which the whole weight of a body appears to act.

Question 15

Friction

Answer 15

A force that opposes the motion of a body.

Question 16

Moment of a force

Answer 16

Force multiplied by the perpendicular distance to the fulcrum.

Question 17

Lever

Answer 17

Rigid body that is free to rotate about a fixed axis.

Question 18

Couple

Answer 18

Pair of equal and opposite forces whose lines of action do not coincide (acting in opposite directions).

Question 19

Torque

Answer 19

The torque of a couple is equal to the magnitude of one of the forces multiplied by the distance between them.

Question 20

Density

Answer 20

Mass per unit volume.

Question 21

Pressure

Answer 21

Force per unit area

Question 22

Buoyancy

Answer 22

The upward force on a body that is wholly or partially immersed in a fluid.

Question 23

Work

Answer 23

The product of force and displacement.

Question 24

Energy

Answer 24

Ability to do work.

Question 25

Inertia

Answer 25

Refusal to change state of motion.

Question 26

Kinetic energy

Answer 26

Energy a body has due to its motion.

Question 27

Potential energy

Answer 27

Energy a body has due to its position or condition.

Question 28

Power

Answer 28

Rate at which work is done

Question 29

Angle

Answer 29

Measured in radians, is equal to the arc length divided by the radius.

Question 30

Angular Velocity

Answer 30

Rate of change of angle.

Question 31

Linear Velocity

Answer 31

Speed of the particle in a direction perpendicular to the radius at that point.

Question 32

Periodic time

Answer 32

Time taken for one complete revolution, cycle or oscillation.

Question 33

Centripetal Acceleration

Answer 33

Acceleration for an object travelling in uniform circular motion; it is directed towards the centre of the circle.

Question 34

Centripetal force

Answer 34

Force required to maintain uniform circular motion; it is directed towards the centre of the circle.

Question 35

Elastic Constant

Answer 35

Constant of proportionality between the applied force and the resulting displacement of a given spring.

Question 36

Elasticity

Answer 36

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 37

Simple harmonic motion

Answer 37

Where the acceleration of a body towards a particular point is proportional to the displacement from that point.

Question 38

Amplitude

Answer 38

Maximum distance that an object moves from its equilibrium position.

Question 39

Frequency

Answer 39

Number of cycles (or oscillations) the object completes per unit time.

Question 40

Period

Answer 40

The *period* of a particle executing SMH is the time taken for one complete oscillation.