On Level Fluid Exam

Which of the following statements about floating objects is correct?

• The object’s density is greater than the density of the fluid on which it floats.

• The object’s density is equal to the density of the fluid on which it floats.

• The displaced volume of fluid is greater than the volume of the object.

• The buoyant force equals the object’s weight.

For incompressible fluids, density changes little with changes in

• depth.

• temperature.

• pressure.

• free-fall acceleration.

A buoyant force acts in the opposite direction of gravity. Therefore, which of the following is true of an object completely submerged in water?

• The net force on the object is smaller than the weight of the object.

• The net force on the object is larger than the weight of the object.

• The net force on the object is equal to the weight of the object.

• The object appears to weigh more than it does in air.

What determines whether an object will sink or float?

• The net force, or the apparent weight acting on the object, determines whether an object sinks or floats.

• This is not the answer.

Which of the following properties is not characteristic of an ideal fluid?

• laminar flow

• turbulent flow

• nonviscous

• incompressible

Which of the following statements is not correct?

• A fluid flows.

• A fluid has a definite shape.

• Molecules of a fluid are free to move past each other.

• A fluid changes its shape easily.

Which of the following is a fluid?

• helium

• ice

• iron

• gold

Why does the lift on an airplane wing increase as the speed of the airplane increases?

• The pressure behind the wing becomes less than the pressure in front of the wing.

• The pressure behind the wing becomes greater than the pressure in front of the wing.

• The pressure above the wing becomes less than the pressure below the wing.

• The pressure above the wing becomes greater than the pressure below the wing.

Which of the following is not an example of turbulent flow?

• a river flowing slowly in a straight line

• a river flowing swiftly around rocks in rapids

• water flowing unevenly from a fully opened faucet

• smoke twisting as it moves upward from a fire

Which of the following is not an example of laminar flow?

• a river moving slowly in a straight line

• smoke rising upward in a smooth column through air

• water flowing evenly from a slightly opened faucet

• smoke twisting as it moves upward from a fire