Science 8 Q1 Module 3: Potential and Kinetic Energy PDF

8 Science Quarter 1 – Module 3: Potential Energy and Kinetic Energy Science – Grade 8 Alternative Delivery Mode Quarter 1 – Module 3: Potential Energy and Kinetic Energy First Edition, 2020 Republic Act 8293, section 176 states that: No copyright shall subsist in any wo...

8 Science Quarter 1 – Module 3: Potential Energy and Kinetic Energy Science – Grade 8 Alternative Delivery Mode Quarter 1 – Module 3: Potential Energy and Kinetic Energy First Edition, 2020 Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit. Such agency or office may, among other things, impose as a condition the payment of royalties. Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this module are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them. Published by the Department of Education Secretary: Leonor Magtolis Briones Undersecretary: Diosdado M. San Antonio Development Team of the Module Writers: Cheri Madleen T. Samaco Editors: Nonita C. Patalinghug, Rhoda M. Delos Santos Reviewers: Bernabe L. Linog, Relyn D. Raza Illustrator: Rosa Mia L. Pontillo Layout Artist: Celeste Faith R. Almanon, Jay S. Ayap Management Team: Francis Cesar B. Bringas Isidro M. Biol, Jr. Maripaz F. Magno Josephine Chonie M. Obseñares Gregoria T. Su Marvilyn C. Francia Nonita C. Patalinghug Printed in the Philippines by ________________________ Department of Education – Caraga Region Office Address: Teacher Development Center J.P. Rosales Avenue, Butuan City, Philippines 8600 Telefax: (085)342-8207/(085)342-5969 E-mail Address: [email protected]  8 Science Quarter 1 – Module 3: Potential Energy and Kinetic Energy Introductory Message For the facilitator: Welcome to the Science 8 Alternative Delivery Mode (ADM) Module on Potential Energy and Kinetic Energy! This module was collaboratively designed, developed and reviewed by educators both from public and private institutions to assist you, the teacher or facilitator in helping the learners meet the standards set by the K to 12 Curriculum while overcoming their personal, social, and economic constraints in schooling. This learning resource hopes to engage the learners into guided and independent learning activities at their own pace and time. Furthermore, this also aims to help learners acquire the needed 21st century skills while taking into consideration their needs and circumstances. In addition to the material in the main text, you will also see this box in the body of the module: Notes to the Teacher This contains helpful tips or strategies that will help you in guiding the learners. As a facilitator you are expected to orient the learners on how to use this module. You also need to keep track of the learners' progress while allowing them to manage their own learning. Furthermore, you are expected to encourage and assist the learners as they do the tasks included in the module. ii For the learner: Welcome to the Science 8 Alternative Delivery Mode (ADM) Module on Potential Energy and Kinetic Energy! The hand is one of the most symbolized parts of the human body. It is often used to depict skill, action and purpose. Through our hands we may learn, create and accomplish. Hence, the hand in this learning resource signifies that you as a learner is capable and empowered to successfully achieve the relevant competencies and skills at your own pace and time. Your academic success lies in your own hands! This module was designed to provide you with fun and meaningful opportunities for guided and independent learning at your own pace and time. You will be enabled to process the contents of the learning resource while being an active learner. This module has the following parts and corresponding icons: What I Need to Know This will give you an idea of the skills or competencies you are expected to learn in the module. What I Know This part includes an activity that aims to check what you already know about the lesson to take. If you get all the answers correct (100%), you may decide to skip this module. What’s In This is a brief drill or review to help you link the current lesson with the previous one. What’s New In this portion, the new lesson will be introduced to you in various ways such as a story, a song, a poem, a problem opener, an activity or a situation. What is It This section provides a brief discussion of the lesson. This aims to help you discover and understand new concepts and skills. What’s More This comprises activities for independent practice to solidify your understanding and skills of the topic. You may check the answers to the exercises using the Answer Key at the end of the module. iii  What I Have Learned This includes questions or blank sentence/paragraph to be filled into process what you learned from the lesson. What I Can Do This section provides an activity which will help you transfer your new knowledge or skill into real life situations or concerns. Assessment This is a task which aims to evaluate your level of mastery in achieving the learning competency. Additional Activities In this portion, another activity will be given to you to enrich your knowledge or skill of the lesson learned. This also tends retention of learned concepts. Answer Key This contains answers to all activities in the module. At the end of this module you will also find: References This is a list of all sources used in developing this module. The following are some reminders in using this module: 1. Use the module with care. Do not put unnecessary mark/s on any part of the module. Use a separate sheet of paper in answering the exercises. 2. Don’t forget to answer What I Know before moving on to the other activities included in the module. 3. Read the instruction carefully before doing each task. 4. Observe honesty and integrity in doing the tasks and checking your answers. 5. Finish the task at hand before proceeding to the next. 6. Return this module to your teacher/facilitator once you are through with it. If you encounter any difficulty in answering the tasks in this module, do not hesitate to consult your teacher or facilitator. Always bear in mind that you are not alone. We hope that through this material, you will experience meaningful learning and gain deep understanding of the relevant competencies. You can do it! iv  What I Need to Know This module was designed and written with you in mind. It is here to help you master potential and kinetic energy. The scope of this module permits it to be used in many different learning situations. The language used recognizes the diverse vocabulary level of students. The lessons are arranged to follow the standard sequence of the course. But the order in which you read them can be changed to correspond with the textbook you are now using. This module contains:  Lesson 1 – Potential Energy and Kinetic Energy After going through this module, you are expected to: 1. Identify and explain the factors that affect potential and kinetic energy. (MELC Week 2-3) 1  What I Know Choose the letter of the correct answer. Write your answers on a separate sheet of paper. 1. An object from a certain height falls freely. Which of the following happens to PE and KE when the object is half on its way down? A. loses PE and gains KE B. gains PE and loses KE C. loses both PE and KE D. gains both PE and KE 2. How do you compare the PE of the moving object at the highest point compared to its KE? A.PE is greater than KE B. PE is equal to KE C. PE is lesser than KE D.KE is greater than PE 3. Which of the following quantities has the greatest influence on the amount of kinetic energy of a car while traveling on a highway? A. mass B. size C. speed D. weight 4. Which of the following pair of quantities are the factors that affect kinetic energy? A. force and distance B. mass and height C. mass and speed D. time and height 2 For Questions 5-6. Refer to the illustration below. 5. Which point has increasing kinetic energy? A. Point C B. Point B C. Point A D. Point A & C 6. Which point has the greatest potential energy? A. Point A B. Point B C. Point C D. Point A & C 7. Which of the following statements is TRUE about potential energy? A. It is dependent on the speed of an object. B. It does not depend on the mass of the object. C. It does not depend on the strength of gravity. D. It is affected by the mass and location of an object with respect to the ground. 8. Which of the following does not affect the amount of potential energy of an object? A. mass B. speed C. height or location D. strength of gravity 3 9. The following applies the concept of potential energy EXCEPT: A. water in a dam B. a person playing the guitar C. a rock sitting at the edge of a cliff D. tree branches high up in a tree 10. What happens to the kinetic energy of an object if its speed is doubled? A. twice as much B. thrice as much C. increases four times D. decreases four times 4  Lesson Potential Energy and 1 Kinetic Energy The word energy is used very often in our daily life. In science, there are many forms of energy however; this module shall only focus on Potential Energy and Kinetic Energy. What’s In Energy: The ability to do work Let us consider the following situations: A fast-moving softball hit a stationary, open door which caused it to move. An object lifted to a certain height using a rope, elevated the object from the ground. A hammer struck on a nail that was placed on a piece of wood, pushed the nail into the wood. A toy car’s key was twisted, placed on the floor and started to move. In all these situations, forces acting on the objects are doing work. An object requires energy to do work. Consider two objects A and B that are about to interact with each other. When object A is pushed, an applied force is doing work on it. Object A possesses kinetic energy while moving towards a stationary object B. In this situation, object A loses energy while object B gains energy. When this happens, energy is transferred from object A to object B. This indicates that any object that has energy can do work. Energy is the ability or capacity to do work. Its unit is the same as the unit of work, expressed in joule (J) in the SI system. One (1) J is the energy needed to accomplish one (1) joule of work. A larger unit of energy called kilojoule (kJ) is sometimes used. One (1) kJ is equal to1000 J. 5  What’s New Activity 1. Energy Crossword Puzzle Objective: Familiarize the words that are associated to the concept of energy. Complete the crossword puzzle below. Across: Down: 1. The product of force and 2. _________ energy is associated displacement is __________. with motion. 4. __________ is the unit of 3. The total __________ energy is energy in SI system. the sum of kinetic and 6. __________ energy is stored potential energy. due to the object’s position. 5. The ability to do work is __________. Notes to the Teacher Provide extra copies of this page for students’ use. 6  What is It Potential Energy In the previous lesson, you were asked if the man lifting the box is doing work on it. Figure 1. A man lifting a box Source: Pia C. Campo, et. Al., A man lifting a box, Science 8 Learner’s Material, Philippines, FEP Printing Corporation, 2016 Which or who is doing work in Figure 1? Is it the table, the box, or the man? Yes, you are correct! The man is doing work on the box. Specifically, the force he applied while lifting is doing work on the box. What is the direction of the force exerted by the man on the box? What is the direction of the motion of the box? Yes, both are directed upward. Work, as discussed earlier, is a way to transmit energy. Hence, when the man exerted force in lifting the box, he loses energy. Work is done on the box, and the box gains energy. You have learned that force of gravity is the force exerted by the Earth on all things. It is always directed downward or towards the center of the Earth. Consequently, when an object is raised from the Earth, the force exerted in lifting the object is equal to its weight, F = Weight = mg The work done in lifting the object is: W = Fd where, the displacement (d) is the height (h) the object is raised. Thus, the work done in lifting the object against the gravitational force is given by W=mgh 7  The work performed in lifting an object is equals to the potential energy the object gains. An object absorbs energy when lifted from the ground and when allowed to fall, it loses energy. The energy that the body gains or losses with respect to its position is called potential energy (PE) and is given by PE=mgh where: PE is the potential energy in joules (J); m is the object's mass in kilograms (kg); g is the acceleration due to gravity which is 9.8 m/s²; and h is the height of the object from the reference point (e.g., ground) in meters (m). Kinetic Energy What is common in the following situations? A running athlete on the track, a flowing water on the ground, a falling coconut from its tree, a rolling rock on the seashore, and a soaring airplane into the air. They are all moving and are acted upon by forces. Any object that moves possesses energy and can do work. An object that moves quicker can do more work than an identical object that moves slowly. How much energy does a moving object possess? We say that the kinetic energy of an object moving at a certain speed is equal to the work done to make it acquire that speed. The energy of a moving object is called energy of motion or kinetic energy (KE). The word kinetic comes from the Greek word kinetikos which means moving. Kinetic energy measures the amount of work the object can do because of its motion. This can be computed using the formula: KE = ½ mv² where: KE is the kinetic energy in joule (J), m is the object's mass in kilogram (kg), and v is the object's speed in meter per second (m/s). From the formula, the kinetic energy of an object depends on its mass and speed. What will happen to the KE of an object if its mass is doubled but the speed remains the same? The KE of an object is also doubled. How about if the speed is doubled but the mass remains the same? The KE of an object increases four times.This means that the greater the mass, the greater the kinetic energy; and the faster the speed the higher the kinetic energy as well. 8  What’s More Activity 2. Kinetic Energy Objective: After performing this activity, you should be able to investigate that increasing or reducing the mass and/or speed affect/s the kinetic energy of the object. The situations and explanations below are introduced to guide and help you answer the questions that follow. Situation A: Two vehicles of different mass moving at same speed. The kinetic energy of a 10,000-kg vehicle is twice as much as the kinetic energy of a 5,000-kg vehicle when both are travelling at the same speed. Why is this so? The 10,000-kg vehicle has twice as much the mass of the 5,000-kg car. Since they are travelling at the same speed, using the formula of kinetic energy, KE = ½mv² = ½(2m)v² Therefore, KE = 2(½mv²). The kinetic energy is doubled. https://pixabay.com/get/57e4d44a4f50ab14f6da8c7dda 35367b1c3cdce65055704b_1280.png?attachment= https://pixabay.com/get/57e4d2464354b108f5d08460da 293277163ddde6535177_1280.png?attachment= 9 Situation B: Two vehicles of the same mass moving at different speed. The kinetic energy of a car travelling at 10 m/s is four times the kinetic energy of a car travelling at 5 ms/s. Why is this so? Car travelling at 10 m/s has twice as much the speed of the other car. Since the mass is the same for both vehicles, using the formula of kinetic energy. KE = ½ mv² = ½ m(2v)² = ½ m (4v²) Therefore, KE = 4(½mv²). The kinetic energy is increased four https://pixabay.com/get/53e2d3414e53a times. e14f6d1867dda35367b1c3cdee45157754 1_1920.png?attachment= Procedures: 1. Complete the table below. Refer to the situations and explanations above to guide and help you determine what happens to kinetic energy of an object when either mass or speed is changed. Use directly the formula of kinetic energy, KE=½mv². Number 1 is done for you. Table 1. Effects of mass and speed to kinetic energy Kinetic Energy (KE) Mass Speed 1. doubled doubled constant 2. constant tripled 3. doubled doubled 4. reduced to ½ reduced to ½ 5. tripled tripled 6. reduced to ½ doubled Questions: 1. Which of the numbers above is KE largest? ___________________ 2. Which of the numbers above is KE smallest? ___________________ 3. Rank the KE of the numbers above from smallest to largest. _________________ 10 Activity 3. Potential Energy Objective: After performing this activity, you should be able to investigate that increasing or reducing the mass and/or height affect/s the potential energy of the object. The situations and explanations below are introduced to guide and help you answer the questions that follow. Situation A: Two objects of different mass are situated at the same height. The potential energy of 20-kg box is twice as much as the potential energy of a 10-kg box when both boxes are of the same height from the ground. Why is this so? The 20-kg box has twice as much the mass of the 10-kg box. Since they are of the same height from the ground, using the formula of potential energy, PE = mgh = (2m)gh Therefore, PE = 2mgh. The potential energy is doubled. Situation B: Two objects of the same mass are situated at different height. The potential energy of the box that is 10 m from the ground is twice as much the potential energy of the box that is 5 m from the ground when both boxes are of the same mass. Why is this so? The box that is 10 m from the ground has twice as much height of the other box. Since mass is the same for both boxes, using the formula of potential energy, https://pixabay.com/get/57e2dc4a4a52ad14f6da8c 7dda35367b1c3cdce75158784b_1280.png?attachme PE = mgh nt= =mg(2h) https://pixabay.com/get/57e5dd424c50b108f5d08 460da293277163ddce0515073_1280.png?attachme Therefore, PE = 2mgh. The nt= potential energy is doubled. 11 Procedure: 1. Complete the table below. Refer to the situations and explanations above to guide and help you determine what happens to potential energy of an object when either mass or height is changed given a constant value of acceleration due to gravity, g = 9.8m/s². Use directly the formula of potential energy, PE = mgh. Number 1 is done for you. Table 2. Effects of mass and height to potential energy Potential Energy (PE) Mass Height 1. doubled doubled constant 2. constant tripled 3. doubled doubled 4. reduced to ½ reduced to ½ 5. tripled tripled 6. reduced to ½ doubled Questions: 1. Which of the numbers above is PE largest? ___________________ 2. Which of the numbers above is PE smallest? ___________________ 3. Rank the PE of the numbers above from largest to smallest. __________________ 12  What I Have Learned Fill in the blanks with the correct answers to complete the statements. Write your answers on a separate sheet of paper. 1. The ____________of the object increases when elevated from the ground to a certain height. 2. An object's potential energy can be computed using the formula____________. 3. Any moving object possesses energy called ____________ and can be computed using the formula ____________. 4. ____________ is the ability or capacity to do work. 5. When an object’s speed doubles, its kinetic energy ____________. 6. When an object’s mass doubles, its kinetic energy also ____________. 7. The more mass an object has when lifted to a certain height, the ____________ potential energy. What I Can Do Activity 4: Potential Energy and Kinetic Energy Identify whether the objects in the given situations possess Potential Energy or Kinetic Energy. Write your answers on a separate sheet of paper. 1. Bird flying 2. Log in a fireplace 3. Watermelon on a desk 4. Car travelling on the highway 5. Car sitting in a driveway 6. Bunch of coconut stick on a table 7. Ball bouncing on the floor 8. Child jumping on his bed 9. Child sleeping on the crib 10. Marble rolling down the ramp 13  Assessment Choose the letter of the correct answer. Write your answers on a separate sheet of paper. 1. The following situations demonstrate potential energy EXCEPT: A. a bullet fired from a gun B. a child at the top of a slide C. a car parked at the top of a hill D. river water at the top of a waterfall 2. The potential energy is the energy an object has due to its __________. A. mass B. motion C. position D. weight 3. The following conditions exhibits kinetic energy EXCEPT: A. water inside a glass B. rolling stone from the hill C. running athlete on the field D. dancing kids in the living room of the house 4. Which of the following quantities, when doubled, has the greatest effect on the amount of kinetic energy? A. mass B. size C. speed D. weight 5. If a green ball is higher from the ground than a yellow ball and both have the same mass, which ball has more potential energy? A. green ball B. yellow ball C. both has the same PE D. both has the same KE 14 6. Which of the following factors does not affect the amount of potential energy of an object? A. gravity B. height C. mass D. speed 7. Which happens to kinetic energy if mass is doubled? A. doubled B. the same C. tripled D. quadrupled 8. Potential energy is the energy of an object based on its ___________. A. height and mass B. mass and speed C. speed and height D. weight and speed 9. Where does a car on a hill have the greatest potential energy? A. top of the hill B. bottom of the hill C. halfway down the hill D. it has the same potential energy at all points 10. Kinetic energy is the energy an object possessed due to its ___________. A. mass B. motion C. position D. weight 15  Additional Activities Activity 5: More About PE and KE Given the pictures below, answer the corresponding questions that follow. Write your answers on a separate sheet of paper. A ball bounces on the ground. At what position (A, B, C ) does the ball have the greatest potential energy? Kinetic energy? Explain your answer. Which bird on the wire has the more potential energy? Prove your answer using the formula of potential energy. https://pixabay.com/get/52e5d3444350ad14f6da8c7dda35367b1c3cdee55a56744c_1280.png?attachment= https://pixabay.com/get/55e0d0444d57b108f5d08460da293277163fdee0505870_1280.png?attachment= Rubric for Scoring Points Description 2 Discussion is complete with no misconception. Discussion is incomplete with minor misconception. 1 0 No discussion 16  17 What’s More Activity 1. Kinetic energy 1. Doubled 2. 9 times the original KE 3. 8 times the original KE 4. 1/8 of the original KE 5. 27 times 6. Doubled Questions: 1. Largest KE: Number 5, 27 times 2. Smallest KE: Number 4, 1/8 of the original KE. 3. Rank KE smallest to largest: 4,1,6,3,2,5 Activity 2. Potential Energy 1. Doubled 2. Tripled 3. 4 times the original PE 4. ¼ of the original PE 5. 9 times original PE 6. Same as initial PE Questions 1. PE largest: Number 5, 9 times the original PE 2. PE smallest: Number 4, ¼ of the original PE 3. PE largest to smallest: 4,6,1,2,4,9 What I have learned C 10. B 9. D 8. 1. potential energy. D 7. 2. PE = m g h. B 6. A 5. 3. kinetic energy B 4. 1 C 3. , 𝐾𝐸 = 𝑚𝑣 2 2 B 2. 4. energy A 1. 5. quadruples What’s New What I Know 6. doubles 7. more Answer Key  18 Additional activities A. The greatest potential energy is at point A, because the ball is at its maximum height. On the other hand, the greatest kinetic energy is at point B, because the ball is at its Assessment What can I do maximum 1. Kinetic energy speed before it 1. A 2. Potential hits the 2. D energy ground. 3. A 3. Potential B. The 120-g bird 4. C energy has three times 5. A 4. Kinetic energy more potential 6. D 5. Potential energy than the 7. A energy 40-g bird. Using 8. A 6. Potential the formula 9. A energy PE=mgh, 10.B 7. Kinetic energy =(3m)gh 8. Kinetic energy Therefore, 9. Potential PE=3mgh.The energy potential energy is 10.Kinetic energy tripled at the same height. References Books Campo, Pia C., et.al.Science Learner's Module 8. Pasig City: Department of Education, 2016. Website “Kinetic and Potential Energy Activities”. Access May 28, 2020https://dcmp.org/guides/TID7457.pdf “Work and Energy”. Access May 28, 2020http://www.ncert.nic.in/ncerts/l/iesc111.pdf “Kinetic and Potential Energy”. Access June 5, 2020 http://phasesofmatter.weebly.com/kinetic--potential-energy.html 19 For inquiries or feedback, please write or call: Department of Education - Bureau of Learning Resources (DepEd-BLR) Ground Floor, Bonifacio Bldg., DepEd Complex Meralco Avenue, Pasig City, Philippines 1600 Telefax: (632) 8634-1072; 8634-1054; 8631-4985 Email Address: [email protected] * [email protected]