# Standards/Plan.

## Presentation on theme: "Standards/Plan."— Presentation transcript:

Standards/Plan

Standards

Standards

Standards

Processes

Standards

Standards

WARM UP

Simple Harmonic Motion (SHM)
1)

Simple Harmonic Motion (SHM)
1)

Warm Up 2) A block is pushed along a horizontal, frictionless surface, with a horizontal Force that varies as a function of time as shown in the graph here. The mass of the bloc is 3kg. If the block was at rest at time t=0, what is the speed of the block at time t=3?

Warm up 2

Warm Up 3) Three blocks of mass m, 2m, and 3m are placed adjacent to each other on a frictionless horizontal surface as shown above. A constant force of magnitude F is applied to the right. Which of the following statements is true?

Warm Up

Warm Up 4) Two masses, M>m, are connected by a light string hanging over a pulley of negligible mass. When the masses are released from rest, the magnitude of the acceleration of the masses is?

Warm Up 5) A mass of 2.0kg is attached to the end of a light cord to make a pendulum 5.0m in length. The mass is raised to an angle of 53 relative to the vertical, as shown, and released. The speed of the mass at the bottom of the swing is:

Warm Up 6) A cannon is mounted on a cart, and carrying a cannonball. The total mass of the cart, cannon, and ball is M, and the cart is rolling with no friction at a velocity v in the positive direction as shown above. The ball, of mass m, is fired with a velocity vball in the positive x direction. What is the velocity of the cart and cannon after the ball is fired?

Warm Up 6)

Warm Up Awesome Gas Video NO WARM UP!

Warm Up a. X = 1/2 L b. X = 2/5 L c. X = 3/5 L d. X = 3/4 L
7) A student lies on a rigid platform of negligible mass, which is in turn placed upon two spring scales as shown above. The left scale at position 0 reads 200N, and the scale on the right at position L, reads 300N. Find the value of X in terms of L. a. X = 1/2 L b. X = 2/5 L c. X = 3/5 L d. X = 3/4 L e. X = 4/5 L PIVOT POINT

Warm Up 8)

Warm Up 8)

Warm Up 9) A pendulum driven clock, located on earth, is set into motion by releasing its 10m long simple pendulum from a maximum angle of less than 10° relative to the vertical. At what approximate time t will the pendulum have fallen to a perfectly vertical orientation? (Use 10 for g)

Warm Up

a,b,c,d a,c,b,d d,b,c,a d,a,c,b Warm Up
10) By visual inspection, order the PV diagrams shown from the most negative work done on the system to the most positive work done on the system. a,b,c,d a,c,b,d d,b,c,a d,a,c,b

Lesson

Announcements Pass Back Fluids Quiz: Thermo Quiz Friday!

What are important quantities in thermodynamics?
Pressure  Atoms colliding w/ wall of a container Temperature  How fast atoms move Volume  How much space atoms “need” to move freely Number of molecules Really big numbers

Kinetic Theory of Gases Assumptions for an IDEAL GAS
1) Atom are bouncy: Elastic collisions between atoms 2) Atoms are spread out: Far away unless colliding 3) Atoms are random: No preferred direction of motion (means pressure is equal everywhere in a container

Calculation – Units to use
Pressure  ALWAYS Pascals (N/m2 ) Temperature  ALWAYS Kelvin (273 + oC) Volume  ALWAYS m3 (Liters/1000) Number of molecules moles or molecules Moles = Molecules/6.02E23 R = 8.31J/molK Kb = 1.38 E-23 J/K

Equation’s so far PV = nRT PV = NkbT P1 V1 / T1 = P2 V2 / T2
M is molar mass

GAS CONTRACTS (WORK ON)
Energy of a Gas ΔU = Q + W U = 3/2 nRT U = 3/2 PV Energy Type (+) (-) U = Internal energy Temp INCREASE TEMP DECREASE Q = HEAT HEAD ADDED HEAT REMOVED W = Work GAS CONTRACTS (WORK ON) GAS EXPANDS (WORK BY)

Gas Process The thermodynamic state of a gas is defined by pressure, volume, and temperature. A “gas process” describes how gas gets from one state to another state.

Isothermal Process (constant temperature)
Hayon: Pull plunger up from halfway (slowly) T1 P V DT = 0 (constant T)

Isobaric Process (constant pressure)
Hayon: Heat up the tank while allowing plunger to move Isobaric Process (constant pressure) P V Isobaric Expansion Isobaric Contraction DP = 0 (constant P)

Isometric Process (constant volume)
Hayon: Push to the top and then heat up or push to the bottom and then cool down P V NO WORK POSSIBLE!! DV = 0 (constant V)

NO HEAT IS TRANSFERED T isotherm P V adiabat ΔU = W Q = 0 (no heat enters or leaves)

U = 3/2 nRT Example Problem
0.25 moles of a gas are kept at 1150K. The gas undergoes adiabatic expansion, reaching a final temperature of 400K. How much work was done on or by the gas? U = 3/2 nRT

WORK = Area under a PV Diagram
Using PV Diagrams Hayon: Test (remember area) and don’t use 1 way valve WORK = Area under a PV Diagram P V (+) = Contract (-) = Expand 200kpa 100kpa 250m2 300m2

Free Response Problems
FR #1 as an Example Web Assign: Thermo Assignment #2 Then skip #2 and go to the back