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Chapter 7: Work and Energy ( Ewen et al. 2005 ). 7.4 Conservation of Mechanical Energy. Objectives: Related kinetic and potential energy to the law of conservation of mechanical energy. Use conservation of energy to solve problems. Law of Conservation of Mechanical Energy.
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Chapter 7: Work and Energy (Ewen et al. 2005) 7.4 Conservation of Mechanical Energy • Objectives: • Related kinetic and potential energy to the law of conservation of mechanical energy. • Use conservation of energy to solve problems.
Law of Conservation of Mechanical Energy • KE and PE are related to the law of conservation of mechanical energy. • Law of conservation of mechanical energy – the sum of the KE and PE in a system is constant if no resistant forces do work.
Example 1 • A pile driver falls freely from a height of 3.50 m above a pile. What is the velocity when it hits the pile?
Example 2 • You accidentally drop a 5.000 kg mass from a hot air balloon 400.0 m ab0ve the ground. Find its KE, GPE and ME before it is dropped AND 5.00 s after it is dropped. (Assume no air resistance.)
Work is done to take the roller coaster car from the beginning of the ride to the top of the structure to give it potential energy. After it leaves the peak of the ride, the sum of its potential energy and its kinetic energy is equal at each point of the ride.
