What could the force be in this case? The weight

What could you substitute in for MASS? Since density is equal to mass over volume, you can substitute volume x density for mass

Suppose the object was a cylinder, could could you find the Volume? Area times the displacement(height)

What is the formula for absolute pressure?

The pressure exerted by a person's lungs can be measured by having the person blow as hard as possible into one side of a manometer.( see page 317 in the blue book and page 315 in the white book for reference as to what a manometer looks like). If a person blowing into one side of an open tube manometer produces a 70 cm difference in heights of the columns of water in the manometer arms, what is the lung pressure?

According to Archimedes, the buoyant force is equal to the ____WEIGHT__________ of fluid it displaces.

Once again, what can you substitute in for the MASS? Density times volume

What is the formula for the buoyant force?

An irregularly shaped piece of metal has a mass of 90 grams in air. It is suspended from a scale and the scale reads 75 grams when the piece is submerged in water. What are the volume and density of the piece of metal?
First you find the weight in air and in water. Subtract the two values to find the BUOYANT force.

What are the 3 points that define an IDEAL fluid?

• non-viscous
• incompressible
• non-turbulent

Fill in the blank: Concerning a closed pipe system, the mass that flows into a region will _EQUAL___________ the mass that flows out of a region.

What is the equation of flow continuity?

Water flows from a 2.0 cm pipe at a speed of 0.35 m/s. How long will it take to fill a 10-L container?

 

What is Bernoulli's Equation?

In an industrial cooling process, water is circulated through a system. If the water pumped from the first floor through a 6.0 cm pipe with a speed of 0.45 m/s under a pressure of 53,157.9 Pa, what will be the pressure on the next floor 4.0 m above in a pipe with a diameter of 2.0 cm?
You first must use the equation for continuity to solve for the velocity of water on the second floor!

Then use Bernoulli's equation to solve for the Pressure. Keeping in mind that the initial height is zero.

 
 
 

What are the units of Q?   JOULES  What are the units of m? KILOGRAMS

What are the units of DT? DEGREES CELSIUS

Re-write the formula above and solve it in terms for c : Q/mDT=c

What are the units of c? J/kgxC

What is the significance of the D? It means CHANGE or DIFFERENCE

According to Conservation of Energy, Heat __LOST___________ equals Heat ____GAINED_________

A thin copper cup of mass 150-g containing 500-g of water is at a temperature of 20 degrees Celsius. A 225-g sample of an unidentified material at 508 degrees Celsius is lowered into the bath and the cup is sealed. After a few minutes, the system reaches a constant final temperature of 40 degrees Celsius. Determine the specific heat of the sample.

How many objects are losing heat?  ONE  How many objects are gaining heat? TWO

Solve for c:

If something has specific heat it MUST be CHANGING in what? TEMPERATURE

If an object is NOT undergoing the answer above it must be involved in what type of heat? LATENT
 

Write the formula for ___LATENT____________ heat. (use answer above)

Q = mL

Re-write the formula above and solve it in terms for L :    L= Q/m

What are the units for L: Joules/Kg

Write the appropriate “ Heat of ………” word for the following processes

Melting = __Fusion_______________ Freezing = ______Solidification____________ evaporating = __vaporization_______________

Condensing = ___condensation_________________

How much heat must be added to a 1.0 Kg mass of ice at – 10 degrees Celsius in order to transform it into 110 degree Celsius steam?
(c(steam) = 2020 J/kgxC)
How many processes or states does this piece of ice go through? FIVE

Solve for Q:

• Mass from periodic table
• Avogadro's # of molecules
• 22.4 Liters of a gas at STP

How many molecules are in 16.3 L of Cl₂ at STP?

Consider the formula PV = nRT

What does P stand for?  Pressure               Units:    Pascals           OR    Newtons/meter

What does V stand for? Volume                 Units:    Meters cubed

What does n stand for? moles

What does T stand for?  temperature        Units: Kelvin

Re-Arrange the formula above and solve for R:                            Units:

If 23.8 grams of Ammonia gas ( NH₃ ) are to be put into a 10.0-L container at a pressure 202.6 kPa, at what temperature should the gas be maintained?

What needs to be determined before you begin this problem? Convert your grams to moles, Liters to cubic meters, and kilopascals to pascals.

Solve for T?

 

What must the units of temperature be in when dealing with gas laws? KELVIN
 

If a gas is placed in a piston at a specific pressure, yet there is no change in volume, the work done by the gas is? ZERO

Losing heat has what sign? NEGATIVE

Gaining? POSITIVE

What is the sign of work if the gas does the work? POSITIVE

What is the sign of work if work is done on the gas? NEGATIVE

Both Q(heat) and W(work) correspond to the transfer of energy.  What do you call the difference of Q and W? (Hint: this answer depends on a change in temperature) The change in internal energy or DU

A cylinder containing a gas is sealed with a nearly frictionless piston at a pressure of 0.20 MPa. The cylinder is placed in contact with a source of heat and the gas very slowly expands, moving the piston, in such a way that the volume changes by 5 x 10^-3 m³ . Assuming the process is isobaric, and given that 300 J of heat enters the system, determine its change in internal energy

What exponent will Mpa get? x 10⁶

What do you have to determine first? The work!  W = PDV
Solve for DU:

Don’t let the sign fool you! This piston expands at the expense of a reduction!

Fill in chart below
 

Process	Isothermal	Isobaric	Isovolumetric	Adiabatic
Constant?	Temperature	Pressure	Volume	Nothing
Changing?	Pressure, Volume	Volume, temperature	Pressure, temperature	Pressure,Volume, Temp.
Special things To remember?	DU=0, Q = W		DV=0, W=0, DU=Q	Q=0, DU= -W

What can you determine when you know what you get OUT of an engine based on what you put IN?
The EFFICIENCY

What do you call the MAXIMUM or IDEAL situation according to your answer above? CARNOT EFFICIENCY

What must you remember about the temperature in an IDEAL situation? They must be in KELVIN

1 mole of an ideal gas is taken through the cyclic process shown to the left.

If the situation involves an ideal gas, what formula do you use? PV=nRT

By what value will you multiply your units of pressure by?1.01x10⁵

At what temperature is point B? 200 K

At what pressure is point B? 1.01x10⁵ Pa

Using the ideal gas law and point B, solve for V1?

Solve for the volume at point A

(a) Compute the work (W) for each of the four processes.
Work is the Area under the line. W = 0 for the process from D to A and from B to C because there is NO CHANGE in volume or NO AREA.

If this process is cyclic, meaning that it returns to its original starting position, what is its change in internal energy?

DU = ZERO

(b) What is the NET work? 3312.8 + (-1656.4) = 1656.4 J
 

(c) What is T3? Since the Volume doubles from C  to D thus the temperature must DOUBLE according to Charles' Law
T3 = 800 K

An internal combustion engine using natural gas and air as a working substance has a temperature in the spark-ignited firing chamber of 2150 K and an exhaust temperature of 900 K.  The difference between the heat supplied and the work done by the engine in one complete cycle is 460 J.

What does the word “difference” suggest? SUBTRACT

What is another way to state “heat supplied”? Heat Absorbed, Heat taken in

If the difference between the heat supplied(Q_h) and the work(W) done by the engine in one complete cycle is 460 J, what are they really saying 460 J is?
The Heat expelled to the COLD RESERVIOR, Q_c = 460 J
If you were asked to find the ideal efficiency, what kind of engine are we suggesting?
Carnot

Solve for the maximum efficiency

How much work is done if the heat input is 790 J?

What is the ACTUAL efficiceny (meaning don’t use Carnot)