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Project 7a: Concept Maps
For today's class to prep for both the group exam and the individual exam, you all are going to create a concept map (imaged above) to demonstrate the connections between concepts we have covered so far. Yous should begin with Fnet = ma as the central concept and work out from there.
Today, we are transitioning into talking about energy and are going to start small and examine energy from a few different scenarios. These scenarios highlight the idea of choosing systems and will ask you to analyze each problem from two different systems. This will hopefully help you all compare and contrast these two different approaches to solving energy problems.
Project 7: Learning issues
- Relationship Between Force and Energy - Work
- Choosing a system
- Conservation of Energy
- Potential and Kinetic Energy
Scenario 7a: Iron Man speeds up a train
Iron Man encounters a train that has run out of fuel 1000 m before the train station. He decides to put on his blasters (which have a force of 2000 N), and he pushes the train for 500 m to get it up to speed. He's hoping that friction for the rest of the way will slow down the train by the time it arrives at the station.
Choice 1: System = train + iron man + Earth Choice 2: System = train
1. For each choice of system above, answer the following questions:
- Is energy conserved in the system? Why/why not?
- Is work done on the system? Is it positive or negative? How do you know?
- Draw the energy bar charts for the scenario.
2. Pick a system to calculate how fast the train will going when it gets to the station.
3. Which system did you choose for your analysis? Why?
Scenario 7b: Hawkeye Launches Arrow
Hawkeye is standing the edge of a tall building (80 m) and needs to fire an arrow into the sky as a warning to the other avengers. He releases the arrow with an initial speed of 50 m/s at an angle of 60 degrees. Consider this situation from the instant after the arrow is launched.
Choice 1: System = Arrow + Earth Choice 2: System = Arrow
1. For each choice of system above, answer the following questions:
- Is energy conserved in the system? Why/why not?
- Is work done on the system? Is it positive or negative? How do you know?
- Draw the energy bar charts for the scenario.
2. Pick a system to calculate the maximum height that the arrow will reach in the sky.
3. Which system did you choose for your analysis? Why?