# Lesson Worksheet: Applications of Viscosity Physics

In this worksheet, we will practice describing the effect of viscosity on fluid flow for vehicular, engineering, and medical applications.

Q1:

If a fluid increases in viscosity, in which of the following ways does this change the fluid’s resistance to deformation?

• AThe resistance of the fluid to deformation is not affected.
• BThe fluid has greater resistance to deformation.
• CThe fluid has less resistance to deformation.

Q2:

Which of the following most correctly describes how the drag force exerted by a fluid on an object moving through the fluid varies with the speed at which the object moves through the fluid?

• ABelow a certain speed, the drag force is proportional to the speed, but above this speed, the drag force is proportional to the square of the speed.
• BThe drag force is proportional to the speed.
• CBelow a certain speed, the drag force is proportional to the square root of the speed, but above this speed, the drag force is proportional to the speed.
• DThe drag force is proportional to the square root of the speed.
• EThe drag force is proportional to the square of the speed.

Q3:

Which of the following most correctly shows how the drag force exerted by a fluid on an object moving through the fluid varies with the speed at which the object moves through the fluid?

• A
• B
• C
• D

Q4:

Thin layers of equal area and thickness of two different-colored oils are placed onto the central region of the top surface of two identical solid disks, as shown in the diagram. The disks are then rotated with equal angular velocities and the oils spread over the surfaces of the disks. The oils have the same density but different viscosities. Which of the oils has the greater viscosity?

• AThe orange oil has the greater viscosity.
• BThe yellow oil has the greater viscosity.
• CBoth oils have the same viscosity.

Q5:

A piston undergoes vertical reciprocal motion within a cylinder in an engine, as shown in the diagram. Where there is contact between the piston and the cylinder, friction is produced. The friction can be reduced by coating the cylinder with a lubricating fluid. If the lubricating fluid used has a low viscosity, which of the following most correctly explains why parts of the cylinder will not retain sufficient lubrication?

• AThe lubricant will mainly stick only to the lower face of the cylinder.
• BThe lubricant will flow from the closed end of the cylinder toward the open end of the cylinder more than in the opposite direction.
• CThe lubricant will flow from the open end of the cylinder toward the closed end of the cylinder more than in the opposite direction.
• DThe lubricant will mainly stick only to the upper face of the cylinder.
• EThe lubricant will flow toward the center of the piston more than in the opposite direction.

Q6:

A piston undergoes horizontal reciprocal motion within a cylinder in an engine, as shown in the diagram. Where there is contact between the piston and the cylinder, friction is produced. The friction can be reduced by coating the cylinder with a lubricating fluid. If the lubricating fluid used has a low viscosity, which of the following most correctly explains why parts of the cylinder will not retain sufficient lubrication?

• AThe lubricant will flow from the upper parts of the cylinder toward the lower parts of the cylinder more than in the opposite direction.
• BThe lubricant will flow toward the center of the piston more than in the opposite direction.
• CThe lubricant will flow from the open end of the cylinder toward the closed end of the cylinder more than in the opposite direction.
• DThe lubricant will flow from the lower parts of the cylinder toward the upper parts of the cylinder more than in the opposite direction.
• EThe lubricant will flow from the closed end of the cylinder toward the open end of the cylinder more than in the opposite direction.

Q7:

Two fluids flow past a circular obstacle. Gray lines represent the direction of fluid flow. Black regions represent solid obstacles to the flow. The only difference between the two fluids is their viscosity. Which of the diagrams shows the fluid with the greater viscosity?

• A
• B

Q8:

Two fluids flow past an airfoil. Gray lines represent the direction of fluid flow. Black regions represent solid obstacles to the flow. The only difference between the two fluids is their viscosity. Which of the diagrams shows the fluid with the greater viscosity?

• A
• B

Q9:

The holes of gas cooker burners are designed to be small so that gas rushes out with .

• Ahigh pressure
• Bhigh temperature
• Chigh speed
• Dhigh volume

Q10:

In the human body, why does the blood flow faster in the main artery than in blood capillaries?

• ABecause the speed of the blood flow varies inversely with the total cross-sectional area of the blood vessels
• BBecause the speed of the blood flow varies directly with the total cross-sectional area of the blood vessels
• CBecause the main artery is shorter in length than the blood capillaries
• DBecause the main artery is longer in length than the blood capillaries

This lesson includes 15 additional questions for subscribers.