Section 5: Materials

Question 1

Equation and units of density.

Answer 1

mass/volume kg m-3

Question 2

What is Hooke’s Law?

Answer 2

the extention of a streched wire, is proportional to the load or force.
F= K 🔺L k= sprig constant in Nm-1

Question 3

What is meant by elastic limit?

Answer 3

If the forces is increased past the elastic limmit, the material will be permanently streched.

Question 4

What is meant by limit of proportionality?

Answer 4

The point beyond which the force is no longer propotional to extention.
Aslon known as Hooke’s law limit

Question 5

What is meant by a deformation being elastic?

Answer 5

The material returns to its original shape once the forces are removed/ no perminent extention

Question 6

What is meant by a deformation being plastic?

Answer 6

The material is permanently streched.

Question 7

What does a tensile force do?

Answer 7

Streches the material.

Question 8

What are the units of tensile stress?

Answer 8

Nm-2

Question 9

What is meant by the yeild point?

Answer 9

The material suddenly starts to strech without any extra load.

Question 10

What does the graph (stress by strain) of a brittle material look like?

Answer 10

A straight line from origin