Week 11 Quiz: Buoyancy

A rock of irregular shape sinks to the bottom of water when placed in it. Which two of the following, when used together, could be used to determine its density?

• Measure the mass of the rock on a scale

• Measure the mass of the beaker of water on a scale

• Place the rock in a beaker and measure the change in height of the water

• Place the rock in a beaker and measure the height of the water above it

The formula for density is...

• mass/ acceleration

• volume/ mass

• mass/ volume

• acceleration/ mass

Which cube is denser?

• A

• B

• They have the same density

What is buoyant force?

• An upward force exerted by fluids on an object.

• A downward force exerted by fluids on an object.

If an object sinks in a fluid, the buoyant force is ____ the

weight of the object.

• greater than

• less than

• the same as

A block of metal is thrown into a lake. What

happens to the buoyant force as it sinks deeper in the

water?

• Increases

• Decreases

• Stay the same

• increase and then decrease

• 800N

• 40000N

• 4000N

• 20000N

A 5 N stone is dropped in a lake and it sinks.

Which of the relationships below is true for the

buoyant force on the stone?

• 𝐹_b = 0

• 𝐹_b = 5

• 𝐹_b is greater than 5

• 𝐹_b is less than 5

What is the magnitude of the buoyant force on a

20 𝑁 ball that is floating in a liquid of density

800𝑘𝑔/𝑚³ .

• 20N

• 40N

• 80N

• 800N

The sum of all forces acting on an object and direction

• Contact Force
• Balanced Force
• Unbalanced Force
• Net Force