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Energy and Motion. Table of Contents 8.2 What Is Energy?. Vocabulary 8.1. Energy: The ability to do work or cause change. Joule : S.I. unit that measures energy Kinetic Energy: Energy that an object has due to its motion.
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Energy and Motion Table of Contents 8.2 What Is Energy?
Vocabulary 8.1 • Energy: The ability to do work or cause change. • Joule: S.I. unit that measures energy • Kinetic Energy: Energy that an object has due to its motion. • Potential Energy: The energy an object has because of its position; also the internal stored energy of an object, such as energy stored in chemical bonds. • Gravitational Potential Energy: Potential energy that depends on the height of an object. • Elastic Potential Energy: The energy of stretched or compressed objects.
How are Energy, Work, and Power Related? Pg. 290 • What is ENERGY? • Energy is the ability to do work or cause change. • Rd. pgs. 290, 291 • When you do work on an object, some of your energy is transferred to that object. • You can think of work as the transfer of energy. • Both work and energy are measured in joules. • S.I. Unit for WORK & ENERGY=JOULES
Formula to Solve for Power pg. 291 • You may recall that power is the rate(speed) at which work is done. Since the transfer of energy is work, then the rate at which energy s transferred, or the amount of energy transferred in a unit of time. • Power = Energy Transferred • Time
What Are the Two Types of Energy? Pg. 292 • Kinetic Energy • The 2 Basic types of energy are: • Potential Energy • Whether energy is kinetic or potential depends on: • The motion, the position, and the shape of the object. • The energy an object has due to its motion is ________energy. • Kinetic energy of an object depends on 2 factors: • its speed (how fast is moving) its mass. r. p 3 &4 • The faster an object moves, the more kinetic energy it has. • Kinetic energy also increases as mass increases.
What Is Energy? Pg. 292 • Kinetic Energy • The kinetic energy of an object depends on its speed and mass. • List the vehicles in order of increasing kinetic energy. • ________________________________________________________________________ • Describe another example of two objects that have different kinetic energies. Explain why their kinetic energies are different. • _________________________________________________________________________________
Formula for Solving for Kinetic Energy • 2 • Kinetic Energy= 1 x Mass x Speed • 2 • Changing the speed of an object will have a greater effect on its kinetic energy than changing its mass by the same factor. This is because speed is squared in the kinetic energy equation.
Potential Energy pg. 294 • Potential energy is energy that results from the position or shape of an object. • This type of energy has the potential to do work. • Gravitational potential energy is the potential energy related to an object’s height. • Force is measured in S.I units= NEWTONS (N) • The gravitational potential energy of an object is equal to the work done to lift it to that height. • You can calculate an object’s gravitational potential energy using this equation. • Gravitational potential energy = Weight × Height
What Is Energy? Pg. 294 What is the SI unit for each quantity?
What Is Energy? Pg. 294 • Figure 3 • Gravitational Potential Energy • The rock climbers have gravitational potential energy, which is potential energy related to an object's height. • Circle the rock climber with the greatest potential energy. Calculate this potential energy. The height to be used is at the rock climber’s lowest foot. ______________________ • 2. Where would the rock climbers at the top have to be to have half as much potential energy?_________________________________________________________________________________________________
Elastic Potential Energy pg. 295 • Figure 4 • Elastic potential energy is the energy associated with objects that can be compressed or stretched. The energy stored in a trampoline is elastic potential energy. • Art in Motion
What Is Energy? Elastic Potential Energy The energy stored in a stretched object, such as the trampoline, is elastic potential energy. Rank the amount of elastic potential energy of the trampoline from greatest to least. (1=greatest) write your answers in the circle