04 - Commen specialist technical priciples

Question 1

what is a static load/force?

Answer 1

a force which does not move

Question 2

what is a dynamic load/force?

Answer 2

a force that moves

Question 3

give an example of a static load

Answer 3

a book edging on a table top

Question 4

give an example of a dynamic load

Answer 4

a book dropped from a roof falling onto a table

Question 5

when does tension occur?

Answer 5

when a pulling force is applied to either end of a material

Question 6

what happens when an object is under tension?

Answer 6

it becomes stretched

Question 7

give two examples of tension

Answer 7

• the rope during a tug of war

- chains supporting a swing

Question 8

define tensile strength

Answer 8

the ability of an object to resist being pulled apart

Question 9

when does compression occur?

Answer 9

when a pushing force is applied to either end of a material (opposite to tension)

Question 10

give 3 examples of objects under compression

Answer 10

• spring in a suspension system
• clove of garlic in a garlic press
• air in a spray deodorant

Question 11

why is holding liquids and gases under compression an economical way of storing them?

Answer 11

• take up less room

- can easily control their release (through valves)

Question 12

define compressive strength

Answer 12

the ability of a material to resist being compressed or squashed

Question 13

when does torsion occur?

Answer 13

when two ends of the material rotate in opposite directions

Question 14

give 2 examples of objects under torsion

Answer 14

• wringing a wet towel

- boats riding over waves

Question 15

what is torsional strength?

Answer 15

the ability of a material to resist being twisted out of shape

Question 16

describe a bending force

Answer 16

• results in both tension and compression (stop think for a minute how)
• top is tension
• underside is compression

Question 17

how is a bending force applied?

Answer 17

• applied to both sides with either upward or downward pressure

Question 18

define stiffness

Answer 18

the ability of a material to resist being bent out of shape

Question 19

describe the direction on a shear force

Answer 19

acts on an object in a perpendicular direction to the length

Question 20

give an example of a shear force

Answer 20

• wind pushing against a tree

Question 21

describe shear forces in terms of joints

Answer 21

materials being pulled apart along different planes or lines (travel in opposite directions)