Topic 4

Question 1

What is upthrust equal to and what is the principle called

Answer 1

Weight of fluid displaced U=W (mg) or U=Vρ

Archimedes principle

Question 2

What is stokes law only used for?

Answer 2

only to small spherical objects moving at low speeds with laminar flow and that viscosity is temperature dependent

Question 3

What is k?

Answer 3

The stiffness constant in hookes law.

Question 4

What is a hydrometer and how does it work?

Answer 4

Instrument used to determine density, sinks in lower density

Question 5

What are streamlines

Answer 5

lines of laminar flow

Question 6

What is viscosity

Answer 6

Frictional force in fluids

Question 7

What is eta

Answer 7

The coefficient of viscosity

Question 8

What is viscous drag

Answer 8

The friction force between a solid and a fluid

Question 9

What is tension

Answer 9

A force in a material that is acting in a direction to extend the material

Question 10

When does a spring stop following hookes constant

Answer 10

When it passes the limit of proportionality or elastic limit

Question 11

What does the gradient on a force extension graph give

Answer 11

Spring constant

Question 12

How is elastic strain energy found

Answer 12

E = 1/2FΔx

Question 13

What is hysteresis

Answer 13

Load history will effect future extension from the same loads

Question 14

What does the area under force-extension and force-compression graphs show

Answer 14

The work done

Question 15

What does the area between two lines on a hysteresis graph give

Answer 15

Energy lost??

Question 16

In order what happens to a material when force is continuasly applied until the material breaks.

Answer 16

Limit of proportionality - beyond this point material may not behave elastically
Elastic limit - beyond this limit material will permanently deform
Yield point - beyond this point material undergoes a large increase in extension
Elastic deformation - Highest value of stress the material hold
Plastic deformation - Fracture of the material