Forces & Elasticity

Question 1

how can materials be deformed?

Answer 1

by compressing, stretching, or bending them

Question 2

what is the difference between ‘elastic’ and ‘inelastic’ deformation

Answer 2

elastic deformation : an object returns to its original shape after the forces have been removed

inelastic deformation / plastic deformation: an object does not return to its original shape after the forces have been removed

Question 3

Hooke’s law:

Answer 3

Hooke’s Law states that the extension of an object is directly proportional to the force applied.

It can be described by the formula:

F=ke

Where F is the force applied to the spring, k is the spring constant, and e is the extension.

Question 4

Extension

Answer 4

the increase in length of a spring when its stretched or decrease in length when compressed

Question 5

What is the minimum number of forces required to stretch, compress, or bend an object?

Answer 5

two

Question 6

spring constant

Answer 6

a measure of how many Newtons of force it would require to stretch (or compress) the object by 1 metre. It has the units N/m.

You can think of it as a measure of how stiff the object is. Objects with a higher spring constant are more stiff, so they require more force to stretch.

Question 7

Which object do you think has the higher spring constant?

A plank of wood

A bungee cord

Answer 7

A plank of wood

Question 8

If you stretch an object too much it can pass its ‘elastic limit’ (also known as the ‘limit of proportionality’).