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Momentum. Image: http://insidethecosmiccube.blogspot.com/2008/01/whats-story-mourning-glory.html. Vocabulary Sheets Due. Sept. 24. Monday. Sept. 8. p = mv. Momentum. p = momentum (kg ·m/s) m = mass (kilograms, kg) v = velocity (meters/second, m/s). Momentum = “amount of motion”.
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Momentum Image: http://insidethecosmiccube.blogspot.com/2008/01/whats-story-mourning-glory.html
Vocabulary Sheets Due Sept. 24
Monday Sept. 8
p = mv Momentum p = momentum (kg·m/s) m = mass (kilograms, kg) v = velocity (meters/second, m/s) Momentum = “amount of motion” • Example: • A superhero of mass 75 kg is moving at 65 m/s. • Find the momentum of our man in tights. • Find the velocity at which a freight train of mass 200,000 kg has the same momentum.
I = FΔt Impulse I = impulse F = force (Newtons, N) Δt = change in time (seconds, s) Thanks Mr. Newton Impulse is change in momentum
As Seen in Action Comics #13 • Superman stops a locomotive. • A 200,000kg train is moving at 15 m/s. After Superman flies into it, the train is moving at 0 m/s. • What impulse did Superman deliver to the train? • If Superman and the train were in contact for 2 seconds, what average force did he exert? • What was the average acceleration of the train during its contact with Superman?
Classwork Page 193 Problems 2-6
Tuesday Sept. 9
Energy Super Heroes Projects due September 24 You must work at home on these. There’s not enough class time. This week: 1. Super power 2. Name & origin story 3. List of concepts your hero can demonstrate.
Energy Super Heroes Presentations start on Sept. 24 • Format: • Slide show & speech • Video • Poster presentation • Others? Image: http://www.coverbrowser.com/covers/action-comics
Superhero Energy Project • Due Monday, September 15 by email or hard copy in class. • From kinetic energy, potential energy, and conservation of energy, write 1 problem at minimum. • From thermal energy, thermodynamics, and specific heat, write 1 problem at minimum. • From momentum, impulse, and conservation of momentum, write 1 problem at minimum. • Looking forward and due on Friday, Sept. 19: From any of the above topics, write 2 additional problems.
Friday Sept. 12
v2 = 2gh How Fast Velocity squared equals two times acceleration due to gravity times height Note: How fast doesn’t care how heavy.
I = FΔt Impulse I = impulse F = force (Newtons, N) Δt = change in time (seconds, s) Thanks Mr. Newton Impulse is change in momentum
The upper limit of how fast. Terminal Velocity How fast? Skydiver with a semi-closed parachute: 195 km/h (120 mph) World record human freefall speed is 988 km/h (614 mph) How long? About 15 seconds It happens when your weight is exactly balanced by an upward force called drag. Source: http://en.wikipedia.org/wiki/Terminal_velocity