Unit 3 Study Guide - Energy Content PDF

You should know Kinetic Energy: Understands the relationship between kinetic energy, mass, and speed. Correlation between an object’s mass and its kinetic energy when its speed is constant Positive Correlation between an object’s speed and its kinetic...

You should know Kinetic Energy: Understands the relationship between kinetic energy, mass, and speed. Correlation between an object’s mass and its kinetic energy when its speed is constant Positive Correlation between an object’s speed and its kinetic energy when its mass is constant Positive Formula for calculating kinetic energy KE=1/2mv^2 Potential Energy: Predicts how relative positions affect an object’s potential energy Correlation between an object’s mass and its gravitational potential energy when height off ground and gravity are constant Positive Correlation between an object’s height off ground and its gravitational potential energy when mass and gravity are constant Positive Formula for calculating gravitational potential energy GPE=mgh Correlation between an elastic object’s stretch/compression and its elastic potential energy Positive Energy Transfer: Understands that when the kinetic energy of an object changes, energy is always transferred to or from the object When does an object have kinetic energy? When it is in motion  Forces transfer kinetic energy between objects and/or locations. An example of this is… Pendulum hitting lego man Energy Transformations: Identifies energy conversions/transformations and apply the law of conservation of energy in a situation There are multiple forms of energy. For example: Chemical energy, mechanical energy, Energy can be transformed from one form to another. For example: Electrical energy to mechanical energy in a fan The law of conservation of energy states: Energy cannot be created or destroyed, but it can be transferred between objects and converted into different types of energy Resources You should be able to answer questions from (and those relating to the big ideas from) the activities/simulations Slides and assignments posted on google classroom Readings: ○ Forms of energy (12/4 assignment on Google Classroom) ○ Energy transformations (12/12 assignment on Google Classroom) Additional notes ○ Forms of energy slides (12/5 on Google Classroom) ○ Forms of energy notes ○ Energy transfer and transformation slides (12/16 on google classroom) Some activities we did ○ Types of energy and calculating energy practice (on paper) Slides on how to calculate posted 12/18 ○ Elastic lab ○ Energy transformation PhET (12/12 assignment on Google Classroom) ○ Pendulum Lab ○ Energy poster analysis questions Practice Questions Try to do these without your notes 1. An object is at rest on the ground. It is not moving. a. Can it have energy? Yes b. If so, what type(s) of energy might it have? If not, why not? Chemical energy 2. 0.15 kg baseball moves at a speed of 20 m/s when it is 10 meters above the ground. On Earth, the acceleration due to gravity is 10 m/s2. a. Calculate the baseball’s kinetic energy. Show work and include the appropriate unit. KE=1/2mv^2, KE=½ X 0.15 X 20^2 = 30 Joules b. Calculate the baseball’s gravitational potential energy. Show work and include the appropriate unit. GPE=mgh, GPE=0.15 X 20 X 10 = 30 Joules. 3. The calculations for kinetic energy are calculated wrong, as it should be 2x3^2/2 if they are doing it that way. 4. Name the energy described Word bank: Chemical | Elastic | Electrical (current) | Gravitational | Light/radiant | Mechanical/motion | Nuclear | Sound | Thermal a. Peary is riding their bike to school. Mechanical/motion b. Peary roasts marshmallows with a fire. Before burning, the wood has ____ energy. Chemical  c. As the wood burns, the energy in part b changes into __ energy and __ energy. Thermal energy and light energy 5. 1 a. Why is step 1 an energy transfer? Electrical energy is transferred from the electric outlet to the microwave. b. Why is step 2 an energy transformation? The microwave transforms electrical energy into radiant energy, warming up the popcorn kernels. c. What is the energy transfer in step 3? Radiant energy is being transferred from the microwave to the popcorn kernels. 6. a. Identify an energy transfer that takes place in the gif The white soccer player transfers energy from his foot to the ball. b. Identify an energy transformation that takes place in the gif  The ball has gravitational potential energy in the air that transforms into mechanical energy. 7. You drop a ball and watch it bounce. You notice that each bounce height is shorter than the one before. Explain why this does not violate the law of conservation of energy. Each bounce height is shorter than the one before because when the ball hits the surface, some energy is transferred from the ball to the surface, lessening the amount of energy the ball has. 8. Skater dog a. Friction transforms kinetic energy into thermal energy. b. How does increasing friction affect the rate of this transformation? Increasing the amount of friction increases the amount of thermal energy transformed from kinetic energy. Additional questions from previous years 9. Identify three different forms of energy represented in the image below. Classify each  example as a type of KE or PE Example KE or PE? Light shines on the pear KE Pear flipping the page of the book KE Pear sitting on chair PE 10. There is a positive correlation between a rubber band’s stretch length and elastic potential energy 11. Identify the energy transformation in the gif: Energy Chemical → Mechani → Electrical → Mechani form cal cal Thermal 12. A dog rides its skateboard.  a. Identify an energy transfer in the gif Energy is moving from the skateboard to the ramp b. Identify an energy transformation in the gif Kinetic energy is transformd into thermal energy 13. Who has more gravitational potential energy: a) 20 kg skater dog at position X with a speed of 15 m/s, or b) 5 kg skater cat at position W with a speed of 30 m/s? Explain how you know. GPE = mgh, skater dog has 5000 Joules of GPE, and skater cat has 7500 Joules of GPE, so skater cat has more gravitational potential energy 14. Who has more kinetic energy a) 20 kg skater dog at position X with a speed of 15 m/s, or b) 5 kg skater cat at position W with a speed of 30 m/s? Explain how you know. KE = 1/2mv^2, skater dog has 2250 Joules of kinetic energy, while skater cat has 2250 Joules of kinetic energy, so they have an equal amount of energy, so this is a trick question. 15. Identify each as an example of energy transfer or energy transformation a. Pendulum bob pushes a lego energy transfer b. Stretched elastic band released energy transformation c. Elastic band hits a cup energy transfer d. Sun warms up a chair energy transfer e. Pendulum bob falling to the ground energy transformation