General Physics 1.4 Density

Question 1

State the equation for density. Give appropriate units.

Answer 1

density (kg/m3) = mass (kg) ÷ volume (m3)

p = m/v

Question 2

Describe a method to determine the density of a regular solid.

Answer 2

• Take measurements of relevant dimensions using a ruler
• Calculate the volume using an appropriate equation
• Measure mass using a balance and calculate
density using o = m/V

Question 3

Describe a method to determine the density of an irregular solid.

Answer 3

• Measure volume by submersion: read the volume of liquid, submerge the solid, then read the change in volume (= volume of object)
• Measure mass using a balance
• Use o = m/v to calculate density

Question 4

Describe a method to determine the density of a liquid.

Answer 4

• Place an empty beaker on top of a balance and zero the device
• Pour liquid into the beaker to determine the mass
• Pour the same liquid into a measuring cylinder and read off the volume
• Use o = m/v to calculate density

Question 5

When do objects float in water?

Answer 5

When the object is less dense than the water displaced by it.