AP Physics Fluid Exam Review

A perpendicular force is applied to a certain area and produces a pressure, P. If the same force is applied to a twice bigger area, the new pressure on the surface is:

P/2

A liquid has a specific gravity of 0.357. What is its density?

357 kg/m³

What is the formula for density?

mass divided by volume

Which of the following could be a correct unit for pressure?

kg/m·s²

If two objects have the same volume but different masses, the one with the greater mass will  have:

a higher density

A stone has a mass of 20 g and a volume of 5 cm³

What is its density?

4 g/cm³

An object will sink in water (density os water is about 1.0 g/cm³) if its density is:

1.5 g/cm³

Which of the following is NOT a unit of density?

N/m²

A block of wood has a density of 0.75 g/cm³ and a volume of 120 cm³

What is its mass?

90g

When a liquid is heated, its density generally:

decreases

How does pressure at the bottom of a container filled with water change if the container is replaced by one with a different shape but the same depth and liquid density?

it remains the same

Pressure measurement is typically expressed in units of:

Pascals

As you decend deeper into a lake, the water pressure increases. This is primarily because:

the weight of the water above you increases

A 100 mm (0.1 m) deep tank is filled with water. Using the density of water as 1,000 kg/m³ and gravitational acceleration as 10 m/s²

what is the pressure at the bottom? Exclude atmospheric pressure.

1,000 Pa

A submarine at a depth of 500 m in the ocean experiences higher pressure than at 100 m. What is the direction of the water pressure exerted on the submarine's hull?

equally in all directions

Which of the following liquids would exert the highest pressure at a depth of 1 meter?

mercury

The pressure in a liquid can be increased by:

applying a force to the surface of the liquid

Why are dam walls built wider at the bottom than at the top?

to withstand the higher pressure at the bottom

According to Archimedes' principle, the buoyant force on a submerged object is equal to:

the weight of the fluid it displaces

An object is neutrally buoyant (will neither sink nor rise) if it:

stays suspended in the liquid

When a boat sails from fresh water to salt water, the boat will float:

higher in the water

A 10-ton ship floating in the ocean experiences a buoyant force of:

10 tons

If an object's density is less than the density of the liquid it is place in, it will:

float

A submerged object weighs 900 N in air and 400N in water. What is the buoyant force acting on it?

500 N

Why does a hollow iron ball float while a solid iron block sink?

the hollow iron ball displaces more weight of water than its own weight

The upward force exerted by a fluid on an object immersed in it is called:

buoyant force

What happens to a floating object's displacement if you decrease its mass?

it displaces less fluid and floats higher

A fish in a lake, normally displaces its own:

both volume and weight of water

According to the Bernoull principle, when the velocity of a fluid increases, what happens to its pressure?

pressure decreases

Which of the following is an appliction of Bernoulli's principle?

Lift generated by an airplane wing

The Bernoulli's equation is a statement of the conservation of:

energy

When water flows through a narrow section of pipe, its speed increases. According to Bernoulli, the pressure in this narrow section will be:

lower than in the wider section

What are the key assumptions required to apply Bernoulli's equation?

steady, incompressible, and non-viscous

If you blow air between two hanging balloons, they will move toward each other. Why?

The fast moving air decreases pressure between them

Water flows at a steady velocity through a horizontal pipe with a changeable diameter. The water velocity is 2 m/s and pressure is 2.5 Pa (Pascals) at point A. If the pressure drops to 1.5 Pa at point B, what is the water velocity at B?

sqr6 m/s

According to Bernoulli's equation for steady irrotational flow of ideal fluids, what is true?

Total energy is constant along a streamline

What is the unit (SI) for surface tension?

N/m

Why do rain drops form spherical shapes?

due to surface tension minimizing surface area

What is the excess pressure inside a soap bubble?

4T/r

How does surface tension change with an increase in temperature?

It decreases.

The force of attraction between the same molecules of a liquid is called:

cohesive force

Which of the following is true for the angle of contact for water on a glass surface?

It is 0°

What happens to the surface tension of water when a detergent is added?

It decreases.

What method is used to determine the surface tension of a liquid?

Jaeger’s method

Why is it easier to float in salt water than in fresh water?

Salt water is denser than fresh water.

A 10-ton ship floating in the ocean experiences a buoyant force of:

10 tons