EPS 7 Lecture Notes - Lecture 32: Wind Turbine, Kinetic Energy, Equivalence Principle

• School: Berkeley
• Department: Earth And Planetary Science
• Course: EPS 7
• Professor: David Romps

Document Summary

Wind mills are used to mill grain or pump water. Wind turbines are used to generate electricity. Where m = mass and v = speed. Definition of a joule j = kg m2/s2. Speed limit is 55 mph = 25 m/s. Kinetic energy of car at that speed limit is x 1500 x 25^2 = 0. 5 mj. What if you are speeding at 80 mph = 36 m/s. Kinetic energy of car that is speeding: = x 1500 x 36^2 = 1. 0 mj. Which has more kinetic energy: a 2 kg mass moving at 1 m/s = x 2 x 1^2 = 1j, a 1kg mass moving at 2 m/s = x 1 x 2^2 = 2j. In a vacuum, objects fall exactly the same, regardless of their mass. Mvi^2 + mghi = mvf^2 + mghf. If vi = 0, then vf^2 = 2g(hi-hf) (independent of mass: different masses behave equivalently)