Topic 7

Question 1

What does stable mean?

Answer 1

Less likely to tip

Question 2

What are the two keys of stability?

Answer 2

● Wide base
● Low centre of gravity

Question 3

What is a centre of gravity?

Answer 3

the specific point where all of
the mass of the structure is evenly distributed around. Engineers must locate and design with the centre of gravity in mind.

Question 4

What causes a structure to be unstable?

Answer 4

If the thrust line from a centre of gravity doesn’t point to a foundation.

Question 5

What is a thrust line (with a centre of gravity)?

Answer 5

line directly down to
Earth from the centre of gravity.

Question 6

What does a foundation do?

Answer 6

the solid base of a structure

Question 7

Name and describe the 3 types of foundations.

Answer 7

● Pilings: they can rest on
bedrock which is solid
● Packed soil or gravel for
roads, dams and other
mass structures
● Footings - they are wider
than the wall

Question 8

What is spin stabilization?

Answer 8

Spin stabilisation: the
tendency of an object that
is spinning on its axis to
move in a particular
manner