Thursday, Feb. 5 th p. 160, 161

Thursday, Feb. 5 th 160 2/5/15 Thurs. L.T.: I can build a faster car with at least 2 redesigns with explanations of how they will increase the speed of the car. DO NOW: How could you increase the potential energy that goes into both the MT and fan cars? Explain. ………………………… Reflection: Was I able to incorporate the 2 redesigns into my new car? How did they contribute to the speed of your car? Did the redesigns help your car the way you had expected? Are there other ideas you want to try? Why? 161 Title: K’Nex Car Redesign Official blueprints approved and taped in here or yesterday’s right side ……………. (tentative) Data: Car T1T2T3Avg. Time Avg. Speed

5 th period DO NOW Wesely: more PE if the car is tall Carter: kinda disagree, if car is taller, it’ll have to be more spread out. The PE will spread out more when it changes to KE Donaven: disagree with Carter bc if more mass is higher, it’ll have more PE than rest of car Anthony: agree with Carter bc more mass on wheels and won’t be able to move easily Lauryn: not sure what you’re saying everyone. PE: E that is stored up and can be released. More PE if you allow it to build up – once you release it, there’ll be more KE. Like the pressure on the MT I was talking about Anthony: agree with Lauryn. Modding your MT so there’s more pressure build up will make car go faster bc more PE Sonney: add more string to increase PE. Chance: If you add more string, the MT swings its arm, after it’s done, the string will keep pulling and the car will keep moving. Lauryn: not if you have more E to make it move. String has nothing to do with it. (not understanding). String allows to go certain distance but not source of car moving. Guys: (disagree with L) You need longer string to keep axle from twirling back on itself and braking (parking) the car Anthony: agrees with both bc emphasis on modding car. More string if you mod car bc arm will be pulled back more. More string is needed to keep puling with arm and not snapping.

4 th period DO NOW Alex: more mass and using a slope will increase PE Jayden: adding height and mass increases PE Hope: increase in mass will decrease PE and create more KE Jera: I agree with others. But what Hope said, if you increase the mass, wouldn’t it decrease the PE? Alex: I think you’re right bc on example, the bigger cat (more mass) would create more KE than smaller cat. Jera: So Hope is right. Maurice: It also says (T and M) more mass = more PE. All PE transforms into KE. Alex: mass? Jayson: snowball was going faster Alex: Tractors (same mass) were going at dif speeds Jera: greater KE = greater speed and mass. Maurice wrong? PE or KE?

3 rd period DO NOW Add another battery for more PE Take the back off MT and have MT arm pull back more Wind up MT car more (tighter than before) Fan car: add more powerful batteries Batteries don’t determine the fan’s power… (some conversation back and forth about this) Add more propellers to fan car (?) What could we do to reduce sliding friction? Smaller wheels bc less mass to decrease friction Point fan angled diagonally down Take off some of the parts

2 nd period DO NOW Taytum: less mass becomes more ability to create more PE Jordan: nitro Andrew: make car smaller but leave fan/MT the same. SO more PE for less mass = greater impact Luis: dif. Elevation, higher elevation Sam: bigger wheels bc longer stride(?) Luis: disagrees with Sam. Bigger wheels have more mass which would slow it down. More friction. Jordan: What Alex was saying.. Less string and less mass to get less friction. Alex: More string for more friction and less mass so gravity doesn’t pull it down

Brainstorm of Redesigns and Rationales RedesignRationale 1.Using sharp edges 2. Divide certain parts 3. Elevate the start of the car 4. Adding another battery 5. Once car is going, then add more mass (Does more KE necessarily mean more speed??) 1.Reduces air friction. Less friction = more motion. 2.reduce mass with reduce sliding friction. Less sliding friction means more motion. 3.More PE (adding gravitational PE to the fan battery/MT arm) 4.2 batteries will have more PE than just 1 5.Increases KE (which we think will increase speed?)

Jobs Everyone: - rough draft blueprints in SNB - inputs idea of how to redesign car Engineer A: - master blueprints (main person who write and draws on main blueprints with other Engineers’ input. Also makes executive decisions if there are arguments.) Engineer B: - master builder (person in charge of building with the help of other Engineers. Does not mean that they are the only ones that touch materials!) Also gathers materials. Engineer C: - master data collector (the leader who is responsible for collecting data. Orchestrates who does what job and how to keep CVs controlled. Has official record of data in their SNB to share with others) Other jobs that may be needed: massing objects, getting approval from CEO, gathering tape, fixing fan, MT, sweeping, calculating speed, timing, etc.

Order of Events 1. Blueprints: (Leader: Engineer A) - Wednesday - rough drafts in everyone’s SNBs - official blueprints made and approved by CEO 2. Building: (Leader: Engineer B) – Thursday/Friday - parts collected and built according to official blueprints 3. Data Collection: (Leader: Engineer C) – Thursday/Friday - car taken to track and tested over 2 meter track for 3 trials - calculations made to determine avg. speed. - discussion and decisions made of how to improve speed even more

Blueprint Requirements: 1. A diagram of your new car design 2. Make sure both Engineers have a rough draft in both SNBs before getting the official blueprints. Be specific! Once the official blueprints are done, bring them to the CEO for your StitchStamp of Approval. Then you may begin building. RedesignRationale 1. Use small wheels 2. Use small wheels 1. Its lighter 2. Less mass = less sliding friction. Less friction allows more motion. How will this change help the car go faster? Note: Make sure your rationale answers the question: How will this change help the car go faster?

Building Your Car Engineer B is the leader but must follow blueprints 1 MT or 1 fan As many parts as are available (within reason – CEO determines) Altering stock cars can be used to save time, but must be restored to their stock car build by the end of the period Everything built must be broken down by the end of each class period Note: CEO may question engineers about redesigns and HOW they will speed up your car!

2 nd period car data Car TypeAvg. Time (sec)Avg. Speed (met/sec) Fan9.81 s s s s = 9.75 sec d/t = 2met/9.75s = 0.21 met/s Mousetrap2.6 s s s = 1.91 sec d/t = 2met/1.91s = 1.05 met/s Original Q: Which will have an overall faster average speed: fan or MT?

3 rd period car data Car TypeAvg. Time (sec)Avg. Speed (met/sec) Fan7.39 s s 5.84 s d/t = 2 met/5.84 s = 0.34 met/s Mousetrap s s 1.72 s d/t = 2 met/1.72 s = 1.16 met/s

4 th period car data Car TypeAvg. Time (sec)Avg. Speed (met/sec) Fan4.30 s s s 4.57 s d/t = 2 met/4.57 s = 0.44 met/s Mousetrap2.24 s s s s 2.79 s d/t = 2 met/2.79 s = 0.72 met/s Fan Car: grams MT Car: grams

5 th period car data Car TypeAvg. Time (sec)Avg. Speed (met/sec) Fan13.41 s s s d/t = 2 met/10.65s = 0.19 met/s Mousetrap1.50 s s s 1.56 s d/t = 2met/1.56s = 1.28 met/s Fan Car: grams MT Car: grams