Kinetics - Definitions

Question 1

Motion

Answer 1

Continuing change of position

Question 2

Uniform acceleration

Answer 2

Motion caused by constant acceleration

Question 3

Uniform circular motion

Answer 3

Motion of an object in a circle at a constant speed

Question 4

Centripetal force

Answer 4

The force necessary to keep an object moving in a curved path and is directed inward to the centre of rotation

Question 5

Centrifugal force

Answer 5

Force equal to centripetal force but acting In the opposite direction

Question 6

Pendulum

Answer 6

A weight suspended in the earths gravitational field which is free to pivot at its top end

Question 7

Angular amplitude

Answer 7

Angular displacement from rest to max swing position

Question 8

Oscillation/vibration

Answer 8

One full swing to and from maximum position

Question 9

Amplitude

Answer 9

The angle between one side and the other side during an oscillation

Question 9

Damping forces

Answer 9

A decrease of vibrations as a result of removing energy through resistance to motion, reducing the amplitude if an oscillation

Question 9

Vibration

Answer 9

Mechanical oscillations about an equilibrium point

Question 9

Length of pendulum

Answer 9

Distance from the pivot to the centre of gravity of the Bob

Question 9

Cycle

Answer 9

The motion completed in one period

Question 9

Frequency

Answer 9

Number if cycles completed in unit time

Question 10

Free vibration

Answer 10

Occurs when a mechanical system is set off with an initial input and then allowed to vibrate freely eg, tuning fork

Question 10

Acoustics

Answer 10

Field of science related to sound and vibration

Question 11

Forced vibration

Answer 11

When an alternating force or motion is applied to a mechanical system eg, washing machine, buildings during an earthquake and transportation vibration

Question 12

Harmonics

Answer 12

Periodic vibrations that repeat at standard intervals

Question 13

Fundamental frequency

Answer 13

The lowest frequency of a periodic waveform

Question 14

Periodic time

Answer 14

Time taken to make one oscillation.

Question 15

Resonance

Answer 15

The tendency of a system to oscillate at maximum amplitude at a certain frequency

Question 16

Velocity ratio

Answer 16

The ratio of the distance moved by the point at which the effort is applied in a simple machine to the distance moved by the point at which the load is applied

Question 17

Actual mechanical advantage (AMA)

Answer 17

The ratio of output force to input force

How much easier it is for the worker

Question 18

Ideal mechanical advantage (IMA)

Answer 18

This is the mechanical advantage that would exist in an ideal world with no friction etc. It is the ratio of the input distance to the output distance

Question 19

First class lever

Answer 19

A lever where the fulcrum is located between the effort and the load

Question 20

Second class lever

Answer 20

A lever where the fulcrum is at one end and the effort is applied at the opposite end, eg a wheelbarrow

Question 21

Third class lever

Answer 21

A lever where the point of effort is between the fulcrum and the load eg, a landing gear retracting mechanism

Question 22

Inclined plane

Answer 22

A surface inclined horizontally at any angle but a right angle

Question 23

Pulley

Answer 23

A wheel over which a rope or chain is pulled in order to lift or lower heavy objects

Question 24

Fixed pulley

Answer 24

A pulley that does not change the amount of force applied but does change its direction

Question 25

Moveable pulley

Answer 25

A moveable pulley increases the amount of force applied but does not change its direction

Question 26

Block and tackle

Answer 26

A pulley system made up of a fixed and moveable pulley

Question 27

Spur gear

Answer 27

Gear that has its teeth cut straight across their circumference and are used to connect two parallel shafts

Question 28

Bevel gear

Answer 28

A gear that has teeth cut into a conical surface known as a pitch zone to transmit power between two shafts at an angle to each other

Question 29

Worm gear

Answer 29

A gear consisting of a toothed wheel worked by a short revolving cylinder that has a screw thread on it

Question 30

Sun and planet gear

Answer 30

The planet gears are in a cage and are driven around by the sun gear and engage at their outer fixed ring gear which does not rotate

Question 31

Efficiency

Answer 31

The ratio of useful energy out to energy in