Materials

Question 1

what is Hooke’s Law?

Answer 1

The extension produced by a material is directly proportional to the force producing the extension up to the limit of proportionality

Question 2

In a force/extension graph for a spring what is the area under the graph

Answer 2

energy stored

Question 3

for springs:
1) what is elastic region
2) what is plastic region

Answer 3

1) region where spring can be stretched at still return to original shape and is still directly proportional to force (still obeys Hookes law)
2) region where spring has been stretched too far and now has a new permanent length

Question 4

What is Young’s modulus?

Answer 4

ratio of stress to strain of a material obeying Hooke’s Law.

Question 5

How to calculate Young’s modulus?
(including units)

Answer 5

Stress/strain (Pascals)
-strain =extension/original length (no units, it is a ratio)
-stress=force/cross-sectional area (NM^-2 or Pa)

Question 6

how to calculate energy stored in a spring

Answer 6

1/2 x force x extension
OR 1/2 x spring constant x extension^2