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Warm Up In your own words, what is energy? You don’t have to be right, just write down what you think energy is. How do you think energy different from.

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Presentation on theme: "Warm Up In your own words, what is energy? You don’t have to be right, just write down what you think energy is. How do you think energy different from."— Presentation transcript:

1 Warm Up In your own words, what is energy? You don’t have to be right, just write down what you think energy is. How do you think energy different from power? Again, you don’t have to be right, just write! How often do you think the answer to a question on a test is “not enough information given?” Glue in the purple quantity chart under your warm up.

2 Energy SWBAT… Investigate examples of kinetic and potential energy and their transformations

3 What is energy? Energy is the ability of a system to do work.
Remember W = F•d Since it’s the systems ability to do work, the unit of energy is also the Joule (J). Work = Change in Energy W = ∆Energy

4 Types of Energy Potential-Energy from an objects position
Kinetic-Energy from an objects movement Chemical-Energy stored in an objects chemical makeup Thermal-Energy due to an objects temperature

5 Potential Energy Potential energy is any energy stored due to an objects position.

6 Gravitational Potential Energy
Gravitational potential energy is energy stored as the result of an objects height. PEgrav = mass•g•height PEgrav = m•g•h Since an objects weight is equal to m•g: PEgrav = FW•h

7 The relationship Gravitational potential energy is directly proportional to the mass (m). As the mass increases, so does the potential energy. Gravitational potential energy is directly proportional to the height (h). As the height increases, so does the potential energy.

8 Example A cart is loaded with a brick and pulled at constant speed along an inclined plane to the height of a seat-top. If the mass of the loaded cart is 3.0 kg and the height of the seat top is 0.45 meters, then what is the potential energy of the loaded cart at the height of the seat-top? PEgrav = m•g•h PEgrav = (3.0 kg)•(9.8 m/s2)•(0.45 m) PEgrav = 13.2 J

9 Elastic Potential Energy
Elastic potential energy is energy stored in elastic materials as the result of their stretching or compressing. PEspring = ½•k•x2 Where k is the spring constant and x is the distance compressed

10 The relationship Elastic potential energy is directly proportional to the spring constant (k). As the spring constant increases, so does the potential energy. Elastic potential energy is directly proportional to the square of the distance compressed (x). As the distance compressed increases, so does the potential energy.

11 Example A spring with a spring constant 2 N/m is compressed 0.25 m. How much potential energy is stored by the spring? PEspring = ½•k•x2 PEspring = ½•(2 N/m)•(0.25 m)2 PEspring = J

12 Kinetic Energy Kinetic energy is the energy of motion.
KE = ½•mass•velocity2 KE = ½•m•v2

13 The relationship Kinetic energy is directly proportional to the mass (m). As the mass increases, so does the kinetic energy. Kinetic energy is directly proportional to the square of the velocity (v). As the velocity increases, so does the kinetic energy.

14 Example Determine the kinetic energy of a 625-kg roller coaster car that is moving with a speed of m/s. KE = ½•m•v2 KE = ½•(625 kg)•(18.3)2 KE = 104,653.1 J

15 Name Mass (kg) Velocity (m/s) Kinetic Energy (J)


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