Mechanical Energy - Berkner's Base for Physics and Math · 2019. 11. 7. · Mechanical...
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Mechanical Energy.notebook 1 May 23, 2013 May 228:44 AM Mechanical Energy Physics 20 May 228:44 AM • is the sum of the potential and kinetic energy in a system • the mechanical energy in a system is constant Mechanical Energy
Transcript of Mechanical Energy - Berkner's Base for Physics and Math · 2019. 11. 7. · Mechanical...
Mechanical Energy.notebook
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May 228:44 AM
Mechanical Energy
Physics 20
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• is the sum of the potential and kinetic energy in a system
• the mechanical energy in a system is constant
Mechanical Energy
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Consider:• A ball is dropped from the top of a tall building:
• Ball has potential energy only.
• Ball has potential energy and kinetic energy.
• Ball has kinetic energy only.
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• Energy cannot be created or destroyed it only changes from one form into another.
Law of Conservation of Energy
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• a. What is the speed of the ball when it hits the ground? (use conservation of energy)
1.A ball has a mass of 120 g and is dropped from the top of a building 60 m tall.
The maximum potenal energy will be equal to the maximum kinec energy
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b. What is the speed of the ball when it is 15 m above the ground?
• - when the ball is 15m above the ground it will have both potential energy and kinetic energy
notice that the masses cancelled from all three terms
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2. A heavy pendulum is raised to a height of 20 cm above equilibrium.
a. What is the speed of the ball when it reaches equilibrium?
20 cm
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b. At what height will the pendulum have a velocity of 1.5 m/s?
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Assignment: Workbook p. 179 #5, 6, 8 and p. 193 #2, 5, 6
