5.2 Buoyancy

What is the definition of a fluid?

• A solid object that can flow

• A liquid or a gas that can flow

• A substance that sinks in water

• A substance that floats in air

What is the buoyant force?

• A downward force acting on an object

• An upward lifting force that acts on an object when it pushes aside a fluid

• The force that causes an object to sink

• The force that determines the weight of a fluid

When a rock is completely underwater, it displaces an amount of water that is equal to its ________.

• Weight

• Volume

• Density

• Mass

Why does a rock sink in water?

• Because its weight is greater than the weight of the water it displaces

• Because it has a smaller volume than the water it displaces

• Because it has a higher density than the water it displaces

• Because it has a lower buoyant force than the water it displaces

What determines whether an object will float or sink?

• Its weight

• Its volume

• Its density

• Its mass

When an object is less dense than the fluid it is in, it will ________.

• Sink

• Float

• Stay suspended

• Change shape

When an object is more dense than the fluid it is in, it will ________.

• Sink

• Float

• Stay suspended

• Change shape

What does it mean to have neutral buoyancy?

• To sink to the bottom

• To float on the surface

• To have the same density as the surrounding water

• To have no buoyant force