YEAR 9 – Topic 2 – Density and Presssure

Question 1

What is density?

Answer 1

Density is the amount of mass per cm3 or m3.

Question 2

What is the the triangle for density?

Answer 2

..          /\
          /M\
        /\_\_\_\
      / R | V \
     ————

Question 3

What is the equation for density?

Answer 3

. Mass
Density (rho)= ———
. Volume

Question 4

How do you remember the density triangle?

Answer 4

Rho My Viking warship!!!

Or Drive My Van

Question 5

What is density measured in?

Answer 5

Rho (slanted “p”)

Question 6

What is a eureka can?

Answer 6

It is a can with a spout on it. 
.       _|          |
.      //|          |
.     || |          |
.         |\_\_\_\_\_|

Question 7

What does an eureka can do?

Answer 7

It helps you to work out the volume of an irregular object.

Question 8

How do you use an eureka can?

Answer 8

1. Fill it with water until it starts to our other of the spout.
2. Put a measuring cylinder underneath the spout.
3. Put the object into the can.
4. Read how much water came out of the spout in cm3.
   That is the volume of an irregular object!!!

Question 9

What is the density of water?

Answer 9

~1g/cm3

Question 10

How do you know if an object will float or sink in water?

Answer 10

If it is more than 1g/cm3 then it will sink!

If it is less than 1g/cm3 then it will float!

Question 11

On the Earth… how do we calculate weight?

Answer 11

Mass (Kg) x 10 (gravitational field strength) = weight (N)

Question 12

How would you increase the pressure of an object by staying on Earth and not changing its mass?

Answer 12

By decreasing the surface area of the bit of the object that touches the ground.

Question 13

How would you decrease the pressure of an object by staying on Earth and not changing its mass?

Answer 13

By increasing the surface area of the bit of the object that touches the ground.

Question 14

What is the equation for pressure?

Answer 14

. Force
Pressure = ———
. Area

Question 15

What is the way to remember the equation for pressure?

Answer 15

Pretty Fat Animal

Or Pretty Far Away

Question 16

What is the equation for pressure in liquids?

Answer 16

Pressure (in liquids) = Density x gravitational x (change in)height of the
. (Pascals) (Rho) field strength column of liquid
. (N/Kg) (m)

Question 17

How do you go from N/cm2 to KN/m2?

Answer 17

X 10
N/cm2 = 1
KN/m2 = 10

Question 18

What happens with pressure in liquids?

Answer 18

It increases linearly with depth.
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