Chapter 10 Physics Test

Two horizontal pipes are the same length, but pipe B has twice the diameter of pipe A. Water undergoes viscous flow in both pipes, subject to the same pressure difference across the lengths of the pipes. If the flow rate in pipe A is Q, what is the flow rate in pipe B?

16Q

Two horizontal pipes have the same diameter, but pipe B is twice as long as pipe A. Water undergoes viscous flow in both pipes, subject to the same pressure difference across the lengths of the pipes. If the flow rate in pipe B is Q, what is the flow rate in pipe A?

2Q

When a tube of diameter d is placed in water, the water rises to a height h. If the diameter were half as great, how high would the water rise?

2h

An ideal fluid flows at 12 m/s in a horizontal pipe. If the pipe widens to twice its original radius, what is the flow speed in the wider section?

3.0 m/s

Certain insects, such as the water bug, are sufficiently lightweight that they can run on top of water without breaking the surface tension. This is possible because the water, due to surface tension, exerts an upward force on the bottom of the bug's feet. Suppose that the maximum possible upward force on the feet of water bug A is F. Now suppose that water bug B is twice as big as bug A in every dimension. That is, bug B is twice as long, twice as wide, etc. What is the maximum upward force on the feet of bug B?

4.0F

When a small spherical rock of radius r falls through water, it experiences a drag force arv, where "v" is its velocity and "a" is a constant proportional to the viscosity of water. From this, one can deduce that if a rock of diameter 2.0 mm falls with terminal velocity, "v", then a rock of diameter 4.0 mm will fall with terminal velocity ________.

4.0v

An ideal fluid flows at 12 m/s in a horizontal pipe. If the pipe narrows to half its original radius, what is the flow speed in the narrower section?

48 m/s

Substance A has a density of 3.0 g/cm3 and substance B has a density of 4.0 g/cm3. In order to obtain equal masses of these two substances, the ratio of the volume of A to the volume of B will be equal to

4:3

Certain insects, such as the water bug, are sufficiently lightweight that they can run on top of water without breaking the surface tension. Water bug A has weight W. Water bug B is twice as big as bug A, in all dimensions. That is, bug B is twice as long, twice as wide, etc. What is the weight of bug B?

8.0W

Which one of the following is associated with the law of conservation of energy in fluids?

Bernoulli's principle

Salt water has greater density than fresh water. A boat floats in both fresh water and in salt water. Where is the buoyant force greater on the boat?

Buoyant force is same in both

Mass-Density

D=m/v or m=d*v

Which of the following is not a unit of pressure?

N/M

Consider three drinking glasses. All three have the same area base, and all three are filled to the same depth with water. Glass A is cylindrical. Glass B is wider at the top than atthe bottom, and so holds more water than A. Glass C is narrower atthe top than at the bottom, and so holds less water than A. Which glass has the greatest liquid pressure at the bottom?

all 3 have same equal pressure

A piece of wood is floating in a bathtub. A second piece of wood sits on top of the first piece, and does not touch the water. If the top piece is taken off and placed in the water, what happens to the water level in the tub?

does not change

A sky diver falls through the air at terminal velocity. The force of air resistance on him is

equal to his weight

A steel ball sinks in water but floats in a pool of mercury. Where is the buoyant force on the ball greater?

floating on the mercury

What is the difference between the pressures inside and outside the tire called?

gauge pressure

When atmospheric pressure changes, what happens to the absolute pressure at the bottom of a pool?

increases by the same amount

A piece of iron rests on top of a piece of wood floating in a bathtub. If the iron is removed from the wood, what happens to the water level in the tub?

it goes down

You are originally 1.0 m beneath the surface of a pool. If you dive to 2.0 m beneath the surface, what happens to the absolute pressure on you?

it less then doubles

As a rock sinks deeper and deeper into water of constant density, what happens to the buoyant force on it?

it remains constant

Salt water is more dense than fresh water. A ship floats in both fresh water and salt water. Compared to the fresh water, the volume of water displaced in the salt water is

less

Salt water is more dense than fresh water. A ship floats in both fresh and salt water. Compare to the fresh water, the volume of water displaced in the salt water is ?

less

Water flows through a pipe. The diameter of the pipe at point B is larger than at point A. Where is the speed of the water greater?

point A

Water flows through a pipe. The diameter of the pipe at point B is larger than at point A. Where is the water pressure

point B

Pressure is

proportional to its force, ad inversely proportional to its area

Density is...

proportional to its mass and inversely proportional to its volume

Which has the greatest effect on the flow of fluid through a narrow pipe? That is, if you made a 10% change in each of the quantities below, which would cause the greatest change in the flow rate?

radius of the pipe

Three common phases of matter is...

solid, liquid, and gas

When you blow some air above a paper strip, the paper rises. This is because

the air above the paper moves faster and the pressure is lower.

A 10-kg piece of aluminum sits at the bottom of a lake, right next to a 10-kg piece of lead, which is much denser than aluminum. Which one has the greater buoyant force on it? Please explain.

the aluminum

When soup gets cold, it often tastes greasy. This "greasy" taste seems to be associated with oil spreading out all over the surface of the soup, instead of staying in little globules. To us "physikers", this is readily explained in terms of

the increase in the surface tension of water with increasing temperature.

50 cm3 of wood is floating on water, and 50 cm3 of iron is totally submerged. Which has the greater buoyant force on it?

the iron

Two styrofoam balls, of radii R and 2R, are released simultaneously from a tall tower. Which will reach the ground first?

the larger one

Archimedes Principle

upward buoyant force that is exerted on a body immersed in a fluid, is equal to the weight of the fluid that the body displaces

Buoyancy

upward force exerted by a fluid that opposes the weight of an immersed object.

Pascals Principle

when an external pressure is applied to a confined fluid, the pressure in every point in the fluid is increased by that amount

Bernoulli's Principle

when the velocity of a fluid is high, the pressure is low, when the velocity is low, the pressure is high