Density, Upthrust and Viscosity

Question 1

Density is…

Answer 1

Mass per unit volume

Question 2

What is the Density Equation?

Answer 2

Density = Mass / Volume

Question 3

What is the Pressure equation?

Answer 3

Pressure = Force / Area

Question 4

What is Pressure?

Answer 4

is the amount of force applied per unit area

Question 5

How to calculate pressure acting on an object due to a fluid?

Answer 5

Pressure = depth of object in fluid X Density of fluid X Gravitational Field Strength

Question 6

Define Upthrust.

Answer 6

Weight of fluid displaced

Question 7

What is Stokes Law?

Answer 7

F = 6πnrv F - Viscous Drag (N) n - is the Viscosity of the fluid r - Radius of the objectn (m) v - Speed the object is moving at (ms-1)

Question 8

What is Viscosity measured in?

Answer 8

Pas Pascal Seconds

Question 9

Is viscosity temperature dependent?

Answer 9

YES

Question 10

What temperature causes liquids to be less viscous?

Answer 10

Increased temperature

Question 11

What temperature causes liquids to be more viscous?

Answer 11

Lower Temperatures

Question 12

What is Laminar Flow?

Answer 12

Is a flow pattern where all the parts of the fluid are flowing in the same direction - the fluid layers do not mix

Question 13

Diagram showing Laminar Flow?

Answer 13

Question 14

Diagram showing Turbulent Flow?

Answer 14

Question 15

What is Turbulent Flow?

Answer 15

Where all fluid lines are mixed up

Question 16

When does Stokes Law only work?

Answer 16

Applies to:

• Small
• Spherical objects
• Moving Slowly
• With Laminar Flow

Question 17

Does Stokes Law apply to objects moving with Turbulent Flow?

Answer 17

No only objects with Laminar Flow

Question 18

Describe the Experiment used to measure the Viscosity of a Fluid.

Answer 18

• Fill wide clear tube with liquid you want to investigate
• Put rubber band about half way down the tube at a position were the ball will reach terminal velocity
• Place two more bands below first band equal distance between each other, record distance between them. These are the points at which you will record t1 and t2
• Measure diameter of ball bearing and halve it to get the radius
• Drop ball bearing into the tube, start stop watch when ball reaches the furst rubber band, and record time at the other bands.
• REPEAT three times, use magnet to get ball out of the tube.
• If ball falls close to the wall re-do the reading
• Calculate the average time taken to fall between the elastic bands. Use average time and distance between bands, to calculate the average (terminal) velocity.
• You can calculate the viscosity of the liquid.
• using the equation linked below

Question 19

The experiment used to calculate the Viscosity of a Liquid apparatus.

Answer 19