Physics Unit 3 Test
The radius of a pipe is tripled while the pressure difference across the pipe remains the same. The volume flow rate of the pipe increases by a factor of
81
Why will a rolled - up ball of aluminum foil float in water but a solid aluminum ball sink?
Due to the air inside, the average density of the ball is lower than water
At what place in or near the jet engine is gas moving the fastest relative to the flying airplane?
In the plume of exhaust gas flowing out of the engine's outlet duct
Who invented the internal combustion engine?
Otto
Suppose that we are able to send astronauts to Mars and they engage in a game of golf on the red planet's surface. Given that the atmosphere on Mars is considerably less dense than our own, how will the path of the ball be affected?
There is less drag and gravity, so the ball will go further than if there were air
The air in this room consists of countless tiny, independent molecules. You can be sure that all the oxygen molecules will not all shift spontaneously to the other side of the room (leaving you without oxygen) because that would
be extremely unlikely and therefore violate the 2nd law of thermodynamics
This type of heat transfer occurs when heat moves from a molecule in contact with another molecule.
conduction
When cooking a pancake in a pan, the type of heat transfer from the pan to the pancake is
conduction
The first law of thermodynamics is a re - statement of the law of
conservation of energy
A fan blowing on a person makes the person feel cooler because of
convection
The circular motion of water while it boils is an example of
convection
Aerodynamic forces consist of
drag and lift
According to the second law of thermodynamics, it is theoretically possible for an engine to have an efficiency of 100%.
false
Air is an excellent conductor of heat.
false
Convection typically occurs in solids
false
Convection typically occurs in solids.
false
Density is defined as the volume per unit mass.
false
Diastolic blood pressure is the maximum blood pressure and the systolic blood pressure is the minimum blood pressure.
false
Entropy is a measurement of order in a system.
false
Gauge pressure and absolute pressure refer to the exact same value.
false
Heat and temperature have the exact same definition.
false
In pipe flow, flow rate and velocity are not related
false
It typically takes more latent heat to transform a solid into liquid than it does to transform a liquid to a gas.
false
Pressure exerts a force parallel to the area over which the force is applied.
false
The Carnot cycle only uses irreversible processes during the entire cycle.
false
The onset of turbulence inside a pipe and around an object in a fluid happens around the same Reynolds number.
false
Thermodynamics is the study of motion and its relationship to position, velocity, and acceleration.
false
While a phase change is occurring the temperature continues to change.
false
Which Law of Thermodynamics relates change in internal energy to heat added to a system and work done by it?
first
As the Reynolds number increases,
flow is going from being viscous dominated to inertia dominated and therefore turbulent
Suppose you have two containers with liquid in them. One has a density of 760 kg/m3 and the other has a density of 910 kg /m3. If an object floats in one container and sinks in the other, the density of the object
has a value between 760 kg/m^3 and 910 kg/m^3
It is a hot summer day and your friend's apartment has no air conditioning. However, a brand new refrigerator lies unopened in the center of the living room. Being a creative person, your friend closes all the doors and windows of the apartment, unpacks the refrigerator, plugs it in, and turns it on. Your friend then opens the refrigerator door and uses a small fan to circulate the air past the refrigerator and throughout the room. After the refrigerator has operated for a few minutes, the average temperature in the room is
higher than it was before
Flowing honey is less likely to become turbulent than flowing water because
honey's large viscosity favors laminar flow
Lead sinkers actually float on the surface of liquid mercury. Which takes up more space: 1 kg of mercury or 1 kg of lead?
lead
Assume you have three objects with the same mass, but composed of different materials and that the specific heats are ranked by A>B>C where A is greater than B and B is greater than C. If the same amount of energy is transferred into each object which object's temperature will be the highest after the energy is transferred? (Also assume the materials are perfectly insulated from the environment).
object C
The SI Unit for pressure is psi (pound
per square inch) - false
Gravity creates
pressure gradients in fluids
The Earth is warmed by the sun by this type of heat transfer.
radiation
The red light emitted by a hot piece of metal is an example of
radiation
The warmth from a campfire is an example of
radiation
Dimples on a golf ball hit without spin
reduce drag
"The entropy of an isolated system never decreases." Which Law of Thermodynamics is this?
second
You open the refrigerator in your room and put in a case of room
temperature root beer. After an hour, the root beer is ice cold. If your room air did not exchange any heat with the outdoor air during that time, the room air will be - warmer because the refrigerator will have pumped heat out of the root beer and into the room air.
Fluids have viscosity because
the atoms and molecules within the fluid interact with each other, producing internal frictional forces
You are riding in a hot air balloon. You have not used the burner for some time and the balloon begins to sink. Assuming that no air is allowed to leave or enter the balloon,
the average density of the balloon became greater than the surrounding air and the buoyant force on the balloon became less than its weight
To set the world land speed record and travel faster than the speed of sound, the Thrust SSC vehicle used two jet engines that produced about a 250,000 horsepower. The principal reason why this car needed so much power to travel so fast is that
the force of the car's momentum was enormous and the jet engines were needed to supply that force.
To set the world land speed record and travel faster than the speed of sound, the Thrust SSC vehicle used two jet engines that produced about a 250,000 horsepower. The principal reason why this car needed so much power to travel so fast is that
the pressure drag on a car increases dramatically as the car's speed increases
A squirt gun is a simple type of water pump in which a plunger attached to the trigger forces water out of a nozzle and across the room. When you squeeze the trigger of the gun, water squirts out of the nozzle because
the pressure inside the gun is higher than atmospheric pressure
A dense fluid (assume mercury) will sink when poured in a less dense fluid (assume water).
true
A nozzle increases the velocity of pipe fluid flow while dropping the pressure of the fluid.
true
According to Poiseulle's law a small change in pipe diameter can cause a large change in flow rate.
true
An isochoric process happens at a constant volume.
true
Assume an object is suspended in fluid. The bottom of the object feels a larger pressure than the top of the object
true
Assume you have a 100 gram block of ice and a 100 gram glass of liquid water sitting in front of you. In terms of order and disorder the block of ice has more order than the glass of liquid water.
true
Convection currents flow in the atmosphere.
true
Heat transfer is only possible between two objects if the two objects have different temperatures.
true
If two objects come in contact with different initial temperatures, heat transfer will occur.
true
James Joule championed the concept of the mechanical equivalent of heat.
true
Laminar fluid flow is noisier than turbulent fluid flow.
true
Liquids and gases are both considered fluids
true
Liquids and gases are both considered fluids.
true
Turbulent flow is characterized by noisy chaotic mixing fluid flow
true
Turbulent flow is characterized by noisy chaotic mixing fluid flow.
true
The reason fast moving water makes noise is
turbulence
You are camping in the breathtaking mountains if Colorado. You spy an unopened diet soda can floating motionless below the surface of a lake. What is the direction and amount of force the water exerts on it?
up, equal to the can's weight
Why are failures in dams more likely to occur closer to the bottom of the dam?
water pressure is higher at the bottom
