PHYSICS exam 3
Which of the following temperature changes are equivalent?
1 °C = 1 K
Rank, from smallest to largest, the pressures in the tank of motionless fluid shown in the figure.
A>B=C=D>E>F
Bernoulli's principle can be used to explain the lift force on an airplane wing. How must an airplane's wing be designed to ensure that Bernoulli's principle is applicable?
Airplane wings must be designed to ensure that air molecules move more rapidly over the top surface of the wing, creating a region of lower pressure.
Consider three drinking glasses. All three have the same base area, and all three are filled to the same depth with water. Glass A is cylindrical. Glass B is wider at the top than at the bottom, so it holds more water than glass A. Glass C is narrower at the top than the bottom, so it holds less water than glass A. Which glass has the greatest liquid pressure at the bottom?
All three glasses have equal pressure at the bottom.
How a ship floats is described in terms of
Archimedes' principle.
The lift on an airplane wing is an application of
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 the same in both.
What is the relationship between mass, volume, and density?
Density is proportional to mass and inversely proportional to volume.
Which temperature scale does NOT have negative values?
Kelvin temperature scale
A machinist needs to remove a tight fitting pin of material A from a hole in a block made of material B. The machinist heats both the pin and and the block to the same high temperature and removes the pin easily. What statement relates the coefficient of thermal expansion of material A to that of material B?
Material B has a greater coefficient of expansion than does material A.
"An external pressure applied to an enclosed fluid is transmitted unchanged to every point within the fluid" is known as
Pascal's principle.
The hydraulic lift is an application of
Pascal's principle.
The pressure drop in a tube carrying a viscous fluid is described by
Poiseuille's equation.
What is the relationship between area, force, and pressure?
Pressure is proportional to force and inversely proportional to area.
Which of the following statements are true?
Solid ice is less dense than liquid water. Liquid water expands with increasing temperature above 4°C.
A cube of wood is floating on water. A cube of iron is totally submerged in water. The cubes are equal in volume. Which cube has the greater buoyant force acting on it?
The cube of iron has the greater buoyant force acting on it.
A flat metal washer is heated. As the washer's temperature increases, what happens to the hole in the center?
The hole in the center of the washer will expand.
Water flows through a horizontal pipe. The diameter of the pipe at point B is larger than the diameter of the pipe at point A. Where is the speed of the water the greatest?
The speed of the water is the greatest at point A.
If both the pressure and volume of a given sample of an ideal gas are doubled, what happens to the temperature of the gas in Kelvins?
The temperature of the gas in increased by four times its original value.
If the pressure acting on a given sample of an ideal gas at constant temperature is tripled, what happens to the volume of the gas?
The volume is reduced to one-third of its original value
A piece of wood is floating in a tub of water. A second piece of wood rest on top of the first piece; it does NOT touch the water. If the second piece is removed from the first and placed in the water, what happens to the water level in the tub?
The water level remains unchanged.
A jar is completely filled with water, and then it is sealed with a lid. If you push down on the lid with a pressure of 1000 Pa, what happens to the water pressure at the bottom of the jar?
The water pressure at the bottom of the jar will increase by 1000 Pa.
Water flows through a horizontal pipe. The diameter of the pipe at point B is larger than the diameter of the pipe at point A. Where is the water pressure the greatest?
The water pressure is the greatest at point B.
The surface water temperature on a large, deep lake is 3°C. A sensitive temperature probe is lowered several meters into the lake. What temperature will the probe record?
a temperature warmer than 3°C
Consider a flat steel plate with a hole through its center as shown in Fig. 17-1. When the plate's temperature is increased, the hole will
always expand
A metal cylindrical sleeve has an inner radius A and an outer radius B. The metal has a positive thermal expansion coefficient. When the sleeve's temperature increases
both the inner and outer radii increase.
You are driving a late model convertible at the 55 mph limit with its soft ragtop roof up and the windows closed. You observe that the roof
bows outward
Bernoulli's principle is a statement of the
conservation of energy.
The equation of continuity is a statement of which conservation rule applied to fluids in steady laminar flow?
conservation of mass
As the speed of a moving fluid increases, the pressure in the fluid
decreases
Part complete At a fixed depth within a fluid at rest, the pressure pushing upward is
equal to the pressure pushing downward.
Pressure in a fluid decreases with depth.
false
The buoyant force acting on an object is equal to the weight of the object.
false
The specific gravity of a substance is the ratio of the density of that substance to the density of water at 6.0°C.
false
The upward pressure on the bottom surface of a submerged object is less than the downward pressure on its top surface.
false
To determine gauge pressure, add the atmospheric pressure to the absolute pressure.
false
What is the difference between the pressures inside and outside a bicycle tire called?
gauge pressure
If a fluid does not change density as it moves, the fluid is undergoing
incompressible flow.
50 cm3 of wood is floating on water, and 50 cm3 of iron is totally submerged. Which has the greater buoyant force on it?
iron
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
When atmospheric pressure increases, what happens to the absolute pressure at the bottom of a pool?
it increases by the same amount
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 than doubles
As a rock sinks deeper and deeper into water of constant density, what happens to the buoyant force on it?
it remains constant
If all fluid flow within a volume of fluid can be traced as streamlines, the fluid flow is
laminar flow.
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
The three common phases of matter are
solid, liquid, gas
Two systems are in thermal equilibrium. The two systems are at the same
temperature
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.
You have two identical pure silver ingots. You place one of them in a glass of water and observe it to sink to the bottom. You place the other in a container full of mercury and observe that it floats. Comparing the buoyant forces in the two cases you conclude that
the buoyant force in water is smaller than that in mercury.
A valve is closed and the fluid within a pipe is stationary. When the valve is opened, fluid flows through the pipe. What happens to the pressure in the pipe when the valve is opened?
the pressure decreases
Two metal spheres are made of the same material and have the same diameter, but one is solid and the other is hollow. If their temperature is increased by the same amount,
the two spheres remain of equal size.
A cup of water is filled to the brim when an ice cube is placed in it. The tip of the ice cube sticks out of the surface. As the ice melts, you observe that
the water level remains the same
An object floats on a fluid if its density is less than that of the fluid.
true
At any depth in a fluid at rest, the pressure is the same in all directions at the given depth.
true
If a thermometer measures the temperature of two objects as being equal, you can conclude that if the objects are placed in thermal contact, no heat will flow between them.
true
If a thermometer measures the temperature of two objects as being equal, you can conclude that the objects will be in thermal equilibrium if they are brought into thermal contact.
true
If an external pressure is applied to a confined fluid, the pressure at every point within the fluid increases by that amount.
true
The buoyant force occurs because the pressure in a fluid increases with depth.
true
The volume of a gas is inversely proportional to the absolute pressure applied to it when the temperature is kept constant.
true
When a bimetallic strip is heated, the strip will bend toward the side
with the smaller coefficient of linear expansion.
