CP Physics!Good morning! Please…• Take out your Chapter 2 review questions and put them on the side of your desk, to be checked• Answer the warm up questions that are on the slip of paper in the front of the room. Please hand in these slips of paper into the in-box when you are done.
Housekeeping!• Grades are completed for first quarter – Make sure all of your grades have been entered correctly• Chapter 2 test will be on Thursday, 11/10
Agenda• Go over homework solutions• Go over review sheet problems in groups• Go over quiz solutions• Lab report• Catapults• Reaction time activity?• Word scramble activity?
Homework: pg. 64 practice 2F # 1-41. (a) Vf = -42 m/s (b) t = 11s2. (a) vf = -22.1 m/s (b) 2.25 s3. (a) -8.0 m/s (b) t = 1.63 s4. (a) xf = 3.7 m (b) t = 0.77 s
homework1. A robot probe drops a camera off the rim of a 239 m high cliff on Mars, where the free-fall acceleration is -3.7 m/s2. (a) find the velocity with which the camera hits the ground. (b) Find the time required for it to hit the ground.Xi =Xf =Vi = Vf = -42.1 m/sVf = t = 11 sa=t=
homework2. A flowerpot falls from a windowsill 25.0 m above the sidewalk. (a) How fast is the flowerpot going when it strikes the ground? (b) How much time does a passerby on the sidewalk belowhave to move out of the way before the flowerpot hits the ground?Xi =Xf =Vi = Vf = -22.1 m/sVf = t = 2.25 sa=t=
homework3. A tennis ball is thrown vertically upward with an initial velocity of +8.0m/s. (a) What will the ball’s speed be when it returns to its starting point? (b) How long will the ball take to reach its starting point?Xi =Xf =Vi =Vf = Vf = -8.0 m/sa= t = 1.63 st=
homework3. Stephanie hits a volleyball from a height of 0.80 m and gives it aninitial velocity of +7.5 m/s straight up. (a) How high will the volleyball go? (b) How long will it take the ball to reach its maximum height?Xi =Xf =Vi =Vf = Xf = 3.7 ma= t = 0.77 st=
CP Physics Ch. 2 test review Questions pg. 69 # 1, 3, 4, 7-10, 16, 17, 20, 21, 24, 32, 411. Find the total distance and displacement fromthe graph.
CP Physics Ch. 2 test review Questions pg. 69 # 1, 3, 4, 7-10, 16, 17, 20, 21, 24, 32, 411. Sketch position vs. time graphs for… (a) object at rest (b) object with constant positive velocity (c) object with constant negative velocity
CP Physics Ch. 2 test review Questions pg. 69 # 1, 3, 4, 7-10, 16, 17, 20, 21, 24, 32, 417. Velocity can be either positive or negative, depending on thedirection of the displacement. The time interval, Δt, is alwayspositive. Why?
CP Physics Ch. 2 test review Questions pg. 69 # 1, 3, 4, 7-10, 16, 17, 20, 21, 24, 32, 4116. What would be the acceleration of a turtle that is movingwith a constant velocity of 0.25 m/s to the right?
CP Physics Ch. 2 test review Questions pg. 69 # 1, 3, 4, 7-10, 16, 17, 20, 21, 24, 32, 41 8. X = 380 km southPeriod 2 Period 6 Problem to 9. X = 10.1 km east Present 20. t = 4.0 s to Class 21. Vf = +8.6 m/sCesar, Karol Marcus, Sam, Alejandra 8, 9 24. Xf = 93 mAJ, Priscilla Kyle, Tori, Ethenne 20 32. t = 52.4 sDoug, Dylan, Ericka Djeme, Steve 21 41. (a) t = 2.6 sCalyah, JJ, Elainei Amber, Selena, Yama 24 (b) t = 2.7 sHanna, Catie, Conor Rama, John, Michelle, 32Carly, Lovely, Tony Hunter, Tyler, Kaniz 41
What to know for test:• Graphing motion: – You should be able to describe the motion of an object, given its displacement vs. time graph or velocity vs. time graph – What is the slope of a displacement vs. time graph? – What is the slope of a velocity vs. time graph? – What is the area under a velocity vs. time graph? – What is the area under an acceleration vs. time graph?• Use kinematic equations to solve motion problems – What if there is an initial velocity in a free-fall problem?• Study all of your homework problems for Chapter 2• Study your vocabulary!
Grading• Your folders should include… – constant velocity lab – One-dimensional motion quiz: Graded out of 14 points – Kinematic stories – if you do not want your kinematic stories, please donate them to me! – Vocab 17-26 – Free-fall quiz: we will go over solutions – G Whiz lab reports: we will go over lab report: Graded out of 25 points – Catapult grades
G Whiz Lab• Grades are curved: graded out of 25 points instead of 33Does a more massive object fall faster than a less massive one? Were you able to calculate acceleration due to gravity close to the accepted value?
Lab report comments Experimental DesignProblem Definition Section • Materials and safety notes – Make sure to list at least 2-3 safety notes• Problem statement: What for the lab are we trying to do in this • Constants in this lab? – Time interval, dot timer used, if person lab? dropping/holding dot timer were the same, possibly length of tape was held – Prove the accepted value constant of gravity: 9.81 m/s2 – Some people put gravity as constant – this is what we are trying to prove in this lab – See if mass affects though acceleration due to gravity • Procedure should be in sufficient detail so that it could be reproduced• Hypothesis should – What side of the dot timer were the washers? address the problem – How was the dot timer held when paper statement(s) was dropped through? – Draw pictures of procedures if necessary
Lab report comments• Data Presentation Section • Include a “data presentation” section in report. Tell reader to see attached tables & graphs if they are attached at the back of the lab report • Tables – Add a border and center text for tables done on excel – Title tables • Calculations & Equations used – Include this information here instead of in discussion & conclusion section – First show equations, then sample calculations using those equations – Show one sample calc for all calculations done • Graphs – Make sure to give a descriptive title to graphs (not just the default title given by excel)
Lab report • Conclusion Be explicit about how IV affected DV…”The IV, which was the # of washers, had an affect on the DV, the comments distance between dots…” – Refer back to your hypothesis: were your right? • Refer to specific data collected: refer to a specific table Discussion Questions or data point in graph; use this information to support your conclusion• Make sure to answer questions so • Validity: Can someone reproduce this lab and get the that reader knows question without same results? Were there major errors that invalidate looking at question. your data? – Were the # of trials appropriate for this lab?• Use data to support your answers – Were the procedures followed through consistently ?• Do not show calculations in this Were things held constant that should have been? Or should other things have been held constant that were section, just refer to data to support not? your answer. • What errors may have occurred? How can you prevent them?• #4: Must divide the time by 60. • What improvements would you make in the lab in the What should the area under the future to make the lab more valid/repeatable? How velocity vs. time graph give you? would you extend this lab? • Wrap up lab, and connect this lab to an everyday• Many people did not even calculate situation. acceleration due to gravity – must • Some people did not even tell what their calculated calculate it in order to do #1 and 5. gravity values were at all in the report! Must calculate it and discuss your results!