# AP Physics Monday 13.11.18 Standards: b2b2 write down vector equation that results from Newton’s 2nd Law Objective: SWBAT score equivalent of score.

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AP Physics Monday Standards: b2b2 write down vector equation that results from Newton’s 2nd Law Objective: SWBAT score equivalent of score 3 on the test. Warm Up Did you try to solve the rest of the AP Review Questions? If yes, were you able to figure them out? If no, what did you do to prepare for the test. Homework Lab Report Due Tomorrow Agenda Warm Up Take Forces Test

AP Physics Tuesday Standards: 1a1,1a3 Students understand the definition of work. Objective: SWBAT solve problems involving work. Warm Up This was a problem on the test. Find the two unknowns. Fy=? Fx=? W W=50N 30° Homework E#1 Agenda Warm Up Review Test Work Notes Work Guided Practice

AP Physics Wednesday Standards: 1a4: Use Scalar product to calculate the work performed by a specified constant force. Objective: SWBAT represent work graphically by dragging an object a certain distance. Warm Up Find the work done when a 100 N force 50 degrees above the horizontal causes an object to move 40m in the horizontal direction. See diagram below. 100N 50° 40m Agenda Warm Up Review Homework Guided Practice – Work Homework #E2

Warm Up Find Work. AP Physics Thursday Standards: 1a4: Use Scalar product to calculate the work performed by a specified constant force. Ojective: SWBAT 1a4: Use Scalar product to solve problems involving work 70N 60° 120m Agenda Warm Up Review HW Review Lab Solve Work Problems Homework Finish HW #E2

AP Physics Friday Standards: 1b3 Calculate the change in speed or kinetic energy that results from performing a specified amount of work on an object. Objective: SWBAT will be able to solve problems involving Kinetic Energy Warm Up Find the work done by a 2000kg elevator that raises its payload 10 meters while moving at a constant velocity? Agenda Warm Up Review HW Collect Lab Reports Kinetic Energy & Work Homework Thanksgiving HW HW #E3 Next Homework Packet Due Monday: Thankgiving HW, E1-E3 & Any other previous assignment you haven’t turned in.

AP Lab Write Up Rubric Section 4 3 2 1 Question/Hypothesis
The central question the lab is asking is stated along with a plausible hypothesis The central question is stated and something resembling a hypothesis is stated Only the central question is stated The section is missing or contains the wrong central question. Materials/Procedures The procedures are written step by step in complete sentences and the materials are clearly listed. The procedures and materials are listed but unorganized. The procedure does not explain the lab Either the procedures or the materials are incomplete. Only procedures are present, or only materials are present. Data Collection The lab contains a table and a graph that represents the data accurately and is labeled correctly with the equation of the line written. The lab contains a table and a graph but it may be missing some labels and the graph may not be done correctly. The lab is missing a graph completely. The data is incomplete. Calculations Students have all calculations completed, with work shown, and they are correct. Students have all calculations completed and at least half are done correctly and all work is shown. Students do not have all calculations completed, and little work is shown. Calculations section is mostly or entirely missing. Analysis The student gives evidence from their lab data why their hypothesis is true, false, or inconclusive. The discuss the relationships between the variables that were graphed and if linear they write down the equation of the line. The students gives evidence from their lab data and attempts to prove that the hypothesis is false, true or inconclusive, but the data is misapplied and doesn’t support their claim. For linear graphs, no equation is given. This section discusses whether the hypothesis is true, inconclusive, or false but no data is used to support the hypothesis and any reference to the graph or the data is too general to be helpful. This section is omitted or the student may mention the hypothesis and its validity, but doesn’t explain or the explanation is not plausible Conclusion The conclusion includes a summary of your lab results, (which will include numbers or equations), gives %error and discusses sources of error. It also gives a suggestion about how to improve the lab. The conclusion includes a summary of your lab results. It includes data. % error is given. Either and least 1 source of error discussed or a suggestion is given to improve the lab. The conclusion includes a summary and either % error, or mentions types of error, or mentions improving the experiment. The conclusion is omitted or only includes a brief summary.

What is Work? Work is done when… F d F d

What is work? Work is not done when? Fg Fap A B d Fap FN
Now make up a definition of work, write it down to turn in, and prepare to discuss.

Work and the Dot Product
Dot Products occur when you multiply 2 vectors (in this case F & d) and your answer is a scalar (it has no direction.) -A. This equation means that if I lift up a box by applying a Force, I will not be able to move it to the right with my lifting Force. -B. If I push the box to the right with enough Force to move the box, it will move to the right. I will have done work! -C. If is drag a box from a string across the ground, only the horizontal component of the Force I apply will make the box move and therefore do work. θ

Work Practice E#1 Find the work done by the Forces in each diagram? Pay attention to the direction of each of your vectors. It matters. 30N 90m 40N 20m 1. 6. 40N 20m 10° 1N 125m 2 7. 40N 20m 3 8. 70N 30m 40° 70N 5m 4. 9. 80N 40m 135° 40N 20m 5. 55N 10m 35° 10.

Guided Practice A 2000kg box is carried 4m in the air across a warehouse that is 100 m long by a forklift? If it takes 2000 N to move it, how much work is done by the forklift? If the forklift then puts the box down on the ground, how much work is done by gravity on the box? A little box is pulled a distance D by a string at an angle θ by a child distance with a Force F. What is the work done by the child?

Work Practice E#2 A child pulls a wagon full of toys using a rope over his/her shoulder. If the angle of the rope is 60 degrees above the horizontal, how much work will s/he do if he moves the cart 12m after applying 320 N of Force? (ex)The largest palace in the word is the Imperial Palace in Beijing, China, Suppose you were to push a lawn mower around the perimeter of a rectangular area identical to that of the palace, applying a constant horizontal force of 60.0 N. If you did 2.05x105 J of work, how far would you have pushed the lawn mower? If the Imperial Palace is 9.60x102 m long, how wide is it? (1) Lake Point Tower in Chicago is the tallest apartment building in the United States (although not the tallest building in which there are apartments). Suppose you take the elevator from street level to the roof of the building. The elevator moves almost the entire distance at constant speed, so that it does 1.15x105 J of work on you as it lifts the entire distance. If your mass is 60.0 kg, how tall is the building. Ignore the effects of friction. (3) A hummingbird has a mass of about 1.7g. Suppose a hummingbird does 0.15 J of work against gravity, so that it ascends straight up with a net acceleration of 1.2m/s2 How far up does it move? (8) The largest mincemeat pie ever created had a mass of 1.02x103kg. Suppose that a pie with this mass slides down a ramp that is 18.0 m long and is inclined to the ground by 10.0°. If the coefficient of kinetic friction is 0.13, what is the net work done on the pie during its descent? (9) The longest shish kebab ever made was 881 m long. Suppose the meat and vegetables need to be delivered in a cart from one end of this shish kebab’s skewer to the other end. A cook pulls the cart by applying a force of N at an angle of 45.00° above the horizontal. If the force of friction acting on the cart is N, what is the net work done on the cart and its contents during the delivery? (11) width of 78 m. the flag’s mass is 1.24x103 kg, which may explain why the flag has never been flown from a flagpole. Suppose this flag is being pulled by two forces: a force of 8.00x103N to the east and a force of 5.00x103 N that is directed 30.0°south of east. How much work is done in moving the flag 20.0 m directly south?

Kinetic Energy Practice
(Ex) Silvana Cruciata from Italy set a record in one-hour running by running km in h. If Cruciata’s kinetic energy was 694 J, what was her mass? (2) The fastest helicopter, the Westland Lynx, has a top speed of 4.00x102 km/h. If its kinetic energy at this speed is 2.10x107 J, what is the helicopter’s mass. (7) The brightest, hottest, and most massive stars are the brilliant blue stars designated as spetral class O. If a class O star with a mass of 3.38x1031kg has a kinetic energy of 1.10x1042J, what is its speed? Express your answer in km/s (a typical unit for describing the speed of stars) (6) Susie Maroney from Australia set a women’s recond in long-distance swimming by swimming km in h. What was Maroney’s average speed? If Maroney’s mass was 55 kg, what was her kinetic energy?

Work Lab Work = Force * distance -- Objective: Determine the total work done by the Force Meter, after putting successively greater masses on the ForceMeter and graphing the data. You must find the total work from the graph (not by calculations) -- Materials: homeade Force meter, ruler, masses --

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