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PHYS16 – Lecture 17. Ch. 8 Energy Conservation. "It checks out OK on the computer, now let's confirm it with the pendulum.". Energy Pre-question.
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PHYS16 – Lecture 17 Ch. 8 Energy Conservation "It checks out OK on the computer, now let's confirm it with the pendulum."
Energy Pre-question • Two balls have the same mass. Ball 1 is thrown upward at 3 m/s and Ball 2 is thrown downward with 3 m/s. Which Ball reaches the ground with more kinetic energy? • Ball 1 • Ball 2 • Both balls have the same kinetic energy • There is not enough information
Ch. 8 Energy Conservation • Conservative vs. Non-conservative Forces • Conservation of Energy • Basic Equations • Systems without Friction • Systems with Friction • Power
The Trapeze Artist • A trapeze artist launches from a platform with a 40-m-long rope at a 20 degree angle from the vertical. What is the speed of the artist at the bottom? • How high will she go on the other side if there is no air resistance?
Human Canonball? • A cannon ball hangs from a wire. If I hold the cannon ball to my face and let go, will I get hit when the cannon ball swings back? • What two things should I not do…
Human Cannonball • We want to shoot out Evil Knevil (mass = 68.4 kg and length =1.75 m) and have him grab a bar 7.5 m above the cannon. Cannon is 4 m long and equil. position of spring is at the top of the cannon. Knevil depresses the spring 3.3 m. What is the spring constant needed?
Human Cannonball • What is the speed he reaches at the end of cannon?
Monkeys down the slide… • A monkey (23 kg) slides down a 35 degree slide that is 25 m long. When the monkey reaches the bottom he keeps going on a horizontal part. Coefficient of kinetic friction is 0.1 . How far does the monkey go? http://lh3.ggpht.com/_z8sPAlwCN_8/R0wfRchlfVI/AAAAAAAAAcg/gUwvXfLuUxg/CIMG3060.JPG
Conclusions • Conservative vs. Nonconservative Forces • Energy Conservation