Section 2 - Mechanical Devices

Question 1

4 types of motion

Answer 1

Linear
Reciprocating
Oscillating
Rotary

Question 2

How to calculate mechanical advantage

Answer 2

Load / Effort

Question 3

Class 1 Lever?

Answer 3

Load and effort either side of fulcrum
L F E

E.g. seesaw

Question 4

Class 2 Lever?

Answer 4

Effort and fulcrum either side of load
E L F

E.g. wheelbarrow

Question 5

Class 3 Lever?

Answer 5

Load and fulcrum opposite sides of effort
L E F

E.g. tweezers

Question 6

Reverse motion linkage?

Answer 6

Changes direction of input so output is in the opposite direction

Question 7

Parallel linkage?

Answer 7

Input direction is same as output

Question 8

Bellcrank linkage?

Answer 8

Changes input through 90o - changes horizontal motion into vertical motion

Question 9

Crank and slide?

Answer 9

Changes rotary motion into reciprocating

Question 10

Treadle?

Answer 10

Changes rotary motion into oscillating

Question 11

What do cams do?

What is dwell period?

Answer 11

Change rotary into reciprocating motion with use of a follower
Dwell period is part of a cam’s revolution where the follower is stationary

Question 12

Circular cam?
Pear cam?
Snail cam?
Heart cam?

Answer 12

Circular - round, steady rise/fall
Pear - rapid rise/fall followed by long dwell
Snail - long dwell followed by steady rise and sudden drop - one way
Heart - slight rise/fall, no dwell

Question 13

Flat follower?
Knife edge follower?
Roller follower?

Answer 13

Flat - not accurate, lots of friction, copes under heavy load
Knife - very accurate, less friction, does not cope under load
Roller - decent accuracy, little friction, copes decent under load

Question 14

What is gear ratio?

Answer 14

How many times a driven gear is tyrant with one drive gear revolution
E.g. drive = 40 teeth, driven = 20 teeth, 40/20 = 2. One drive = 2 driven

Question 15

What is a pulley?

Answer 15

A groove-rimmed wheel, used with a drive belt to transfer movement
Like a gear without teeth

Question 16

What is Fracking?

Answer 16

Process of drilling into layers of shale rock deep in the earth to release pockets of gas

Question 17

Examples of renewable energy sources?

Answer 17

Wind, solar, tidal, biomass, hydroelectric

Question 18

What is wind energy?

Answer 18

Rotation of the blades turning, driving a generator to produce electricity

Question 19

Pros and cons of wind turbines?

Answer 19

constantly available and sustainable, no cost for wind;;;;;

expensive to build up

Question 20

What is Solar energy?

Answer 20

Convert the suns energy into electrical energy. Clean and renewable, reduces household bills; cost a lot to install

Question 21

What is tidal energy?

Answer 21

Rise and fall of the tides forces through turbines, which drive generators to produce electricity

Question 22

What is hydroelectric power?

Answer 22

Using a dam, once water built up it is released through turbines generating electricity

Question 23

What is biomass?

Answer 23

Growing plants or using animal materials to be burned to produce energy

Question 24

What is nuclear power?

Answer 24

Generates about 11% of the worlds energy. Produces heat through nuclear fission

Question 25

Cons of nuclear power?

Answer 25

expensive, radioactive waste, limited fuel supply