SENIOR HIGH SCHOOL General Physics1 Quarter 1 – Module 2: Title: Vectors Science – Grade 12 Alternative Delivery Mode Quarter 1 – Module 2: Vectors 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 Writer: Loida A. Arce Editor: Jacqueline T. Ureta Reviewer: Alma D. Acuña Illustrator: Name Layout Artist: Name Management Team: Dr. Carlito D. Rocafort Dr. Job S. Zape Jr. Eugene Adrao Elaine Balaogan Dr. Elpidia B. Bergado Noel S. Ortega Dr. Josephine Monzaga Printed in the Philippines by ________________________ Department of Education – Region IV-A Office Address: Telefax: E-mail Address: Capitol Compound, Brgy. Luciano Trece Martires City, Cavite (046) 419 139 / 419-0328 depedcavite.lrmd@deped.gov.ph 12 General Physics1 Quarter 1 – Module 2: Vectors Introductory Message For the facilitator: Welcome to the General Physics 1 12 Alternative Delivery Mode (ADM) Module on Vectors! 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. 2 For the learner: Welcome to the General Physics 1 12 Alternative Delivery Mode (ADM) Module on Vectors! The hand is one of the most symbolized part 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 What I Know What’s In This will give you an idea of the skills or competencies you are expected to learn in the module. 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. 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. What I Have Learned This includes questions or blank sentence/paragraph to be filled in to 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. 3 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! 4 What I Need to Know This module was designed and written with you in mind. It is here to help you master the Vectors. 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. The module is divided into one lesson with subtopics, namely: ● Lesson 1 – Vectors ✔ Vectors and scalars ✔ Addition of Vectors After going through this module, you are expected to: 1. 2. 3. 4. 5. define scalar and vector quantity; differentiate vector and scalar quantities; classify the physical quantities as scalar and vector quantity; determine the magnitude and direction of a given vector; and perform addition of vectors 5 What I Know Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper. 1. Which of the following is an example of a vector quantity? a. acceleration c. volume b. mass d. temperature 2. Displacement is a a. base quantity c. scalar quantity b. derived quantity d. vector quantity 3. Identify the following quantities as scalar or vector: the mass of an object, the number of leaves on a tree and wind velocity. a. vector, scalar, scalar c. scalar, scalar, vector b. vector, scalar, vector d. scalar, vector, vector 4. If two forces 20 N towards North and 12 N towards South are acting on an object. What will be the resultant force? a. 32 N North b. 20 N South c. 32 N South d. 8 N North 5. A student adds two displacement vectors with magnitudes of 3 m and 4 m respectively. Which one of the following could not be a possible choice for the resultant? a. 1.3 m b. 3.3 m c. 5 m d. 6.8 m 6. Find the displacement a hiker walks if he travels 9.0 km north, and then turns around and walks 3.0 km south? a. 0.5 km c. 6.0 km b. 3.0 km d. 12.0 km 6 7. A runway dog walks 0.64 km due N. He then runs due W to a hot dog stand. If the magnitude of the dog’s total displacement vector is 0.91 km, what is the magnitude of the dog’s displacement vector in the due west direction? a. 0.27 km b. 0.33 km c. 0.41 km d. 0.52 km 8. An escaped convict runs 1.70 km due East of the prison. He then runs due North to a friend’s house. If the magnitude of the convict’s total displacement vector is 2.50 km, what is the direction of his total displacement vector with respect to due East? a. 340 SE b. 430 SE c. 470 NE d. 560 NE 9. Two vectors A and B are added together to form a vector C. The relationship between the magnitudes of the vectors is given by A + B = C. Which one of the following statements concerning these vectors is true? a. A and B must be displacements b. A and B must have equal lengths c. A and B must point in opposite directions d. A and B point in the same direction 10. Which expression is FALSE concerning the vectors are shown in the sketch? C B A a. C = A + B b. C + A = -B c. A + B + C = 0 d. C A + B 11. How to add vectors graphically? a. put them in line c. put them tip to tip b. put them tail to tail d. put them tip to tail 12. Which of the following is the definition of vector? a. a quantity that has only magnitude 7 b. a quantity that has both magnitude and direction. c. a quantity that has only one direction d. a quantity that has magnitude but may or may not have direction 13. Which of the following answer contains two scalar quantities and one vector quantity? a. mass, displacement, time c. temperature, displacement, force b. momentum, velocity, acceleration d. time, length, mass 14. A boy walks far 5km along a direction 530 West of North. Which of the following journeys would result in the same displacement? 15. a. 4km N, 3 km W c. 3 km N, 2 km W b. 4 km W, 3 km W d. 3 km N, 4 km W Which procedure should NOT be considered in finding the resultant vector graphically? a. use component method c. use ruler and protractor b. use head to tail method d. use scale Lesson Vectors 8 1 We come into contact with many physical quantities in the natural world on a daily basis. For example, things like time, mass, weight, force, and electric charge, are physical quantities with which we are all familiar. We know that time passes and physical objects have mass. Things have weight due to gravity. We exert forces when we open doors, walk along the street and kick balls. We experience electric charge directly through static shocks in winter and through using anything which runs on electricity. There are many physical quantities in nature, and we can divide them up into two broad groups called vectors and scalars. What’s In Which of the following contains two vectors and a scalar? a. distance, acceleration, speed b. displacement, velocity, acceleration c. distance, mass, speed d. displacement, speed, velocity Notes to the Teacher It is significant that learners had background on the use ruler and protractor in measurement. 9 What’s New Scalar A scalar is a physical quantity that has only a magnitude (size). For example, a person buys a tub of margarine which is labelled with a mass of 500 g. The mass of the tub of margarine is a scalar quantity. It only needs one number to describe it, in this case, 500 g. Vectors are different because they are physical quantities which have a size and a direction. A vector tells you how much of something there is and which direction it is in. Vector A vector is a physical quantity that has both a magnitude and a direction. For example, a car is travelling east along a freeway at 100 km/h. What we have here is a vector called the velocity. The car is moving at 100 km/h (this is the magnitude) and we know where it is going – east (this is the direction). These two quantities, the speed and direction of the car, (a magnitude and a direction) together form a vector we call velocity. Examples of scalar quantities: ● mass has only a value, no direction ● electric charge has only a value, no direction Examples of vector quantities: ● force has a value and a direction. You push or pull something with some strength (magnitude) in a particular direction ● weight has a value and a direction. Your weight is proportional to your mass (magnitude) and is always in the direction towards the center of the earth. 10 What is It Vectors are different to scalars and must have their own notation. There are many ways of writing the symbol for a vector. In this book vectors will be shown by symbols with an arrow pointing to the right above it. For example, F⃗, W⃗ and v⃗ represent the vectors of force, weight and velocity, meaning they have both a magnitude and a direction. Sometimes just the magnitude of a vector is needed. In this case, the arrow is omitted. For the case of the force vector: F⃗ represents the force vector F represents the magnitude of the force vector Graphical representation of vectors Vectors are drawn as arrows. An arrow has both a magnitude (how long it is) and a direction (the direction in which it points). The starting point of a vector is known as the tail and the end point is known as the head. Another common method of expressing directions is to use the points of a compass: North, South, East, and West. If a vector does not point exactly in one of the compass directions, then we use an angle. For example, we can have a vector pointing 40° North of West. Start with the vector pointing along the West direction (look at the dashed arrow below), then rotate the vector towards the north until there is a 40° angle between the vector and the West direction (the solid arrow below). The direction of this vector can also be described as: W 40° N (West 40° North); or N 50° W (North 50° West). Downloaded from and-scalars-0 https://www.siyavula.com/read/science/grade-10/vectors-and-scalars/20-vectors- Drawing vectors 11 In order to draw a vector accurately we must represent its magnitude properly and include a reference direction in the diagram. A scale allows us to translate the length of the arrow into the vector's magnitude. For instance, if one chooses a scale of 1 cm = 2 N (1 cm represents 2 N), a force of 20 N towards the East would be represented as an arrow 10 cm long pointing towards the right. The points of a compass are often used to show direction or alternatively an arrow pointing in the reference direction. Method: Drawing Vectors 1. Decide upon a scale and write it down. 2. Decide on a reference direction 3. Determine the length of the arrow representing the vector, by using the scale. 4. Draw the vector as an arrow. Make sure that you fill in the arrow head. 5. Fill in the magnitude of the vector. Vector Addition Graphical techniques involve drawing accurate scale diagrams to denote individual vectors and their resultants. We will look at just one graphical method: the head-to-tail method. Method: Head-to-Tail Method of Vector Addition 1. Draw a rough sketch of the situation. 2. Choose a scale and include a reference direction. 3. Choose any of the vectors and draw it as an arrow in the correct direction and of the correct length – remember to put an arrowhead on the end to denote its direction. 4. Take the next vector and draw it as an arrow starting from the arrowhead of the first vector in the correct direction and of the correct length. 5. Continue until you have drawn each vector – each time starting from the head of the previous vector. In this way, the vectors to be added are drawn one after the other headto-tail. 6. The resultant is then the vector drawn from the tail of the first vector to the head of the last. Its magnitude can be determined from the length of its arrow using the scale. Its direction too can be determined from the scale diagram. 12 What’s More Activity 1 Categorize each quantity as being either a vector or a scalar. 1. 10 km 2. 60 km/h South 3. 40 mi downward 4. 50 calories 5. 250 bytes 6. 500 m/s NE 7. -9.8 m/s2 8. 1000 kg 9. 1 hour 10. 120 m/s SW ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ ____________________ Activity 2 Determine the magnitude and direction of the following vectors using a ruler and protractor. Use the scale:1 cm = 10 m/s 1. 2. 13 3. 4. Activity 3 Accurately draw scaled vector diagram to represent the magnitude and direction of the following vectors on a graphing paper. 1. 50 m 300 Scale: 1cm = 10m 2. 60 m 1500 Scale: 1cm = 10m 14 3. 140 m/s 2000 Scale: 1cm = 20m 4. 120 m/s 2400 Scale: 1cm = 15m/s 5. 35 m/s 2700 Scale: 1cm = 5m/s Activity 4 Determine the resultant of the following: 1. 30 cm W and 75 cm N 2. 2km E and 4.5 km S 15 What I Have Learned 1. A scalar is a physical quantity with magnitude only. 2. A vector is a physical quantity with magnitude and direction. 3. Vectors may be represented as arrows where the length of the arrow indicates the magnitude and the arrowhead indicates the direction of the vector. 4. The resultant vector is the single vector whose effect is the same as the individual vectors acting together. 16 What I Can Do Give the magnitude and direction from your house to school. resultant vector. 17 Calculate the Assessment Multiple Choice. Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper. 1. Which of the following is an example of a vector quantity? a. acceleration c. volume b. mass d. temperature 2. Displacement is a a. base quantity b. derived quantity c. scalar quantity d. vector quantity 3. Identify the following quantities as scalar or vector: the mass of an object, the number of leaves on a tree and wind velocity. a. vector, scalar, scalar c. scalar, scalar, vector b. vector, scalar, vector d. scalar, vector, vector 4. If two forces 20 N towards North and 12 N towards South are acting on an object. What will be the resultant force? a. 32 N North b. 20 N South c. 32 N South d. 8 N North 5. A student adds two displacement vectors with magnitudes of 3 m and 4 m respectively. Which one of the following could not be a possible choice for the resultant? a. 1.3 m b. 3.3 m c. 5 m d. 6.8 m 6. Find the displacement a hiker walks if he travels 9.0 km north, and then turns around and walks 3.0 km south? a. 0.5 km c. 6.0 km b. 3.0 km d. 12.0 km 7. A runway dog walks 0.64 km due N. He then runs due W to a hot dog stand. If the magnitude of the dog’s total displacement vector is 0.91 km, what is the magnitude of the dog’s displacement vector in the due west direction? a. 0.27 km b. 0.33 km c. 0.41 km d. 0.52 km 8. An escaped convict runs 1.70 km due East of the prison. He then runs due North to a friend’s house. If the magnitude of the convict’s total displacement 18 vector is 2.50 km, what is the direction of his total displacement vector with respect to due East? a. 340 SE b. 430 SE c. 470 NE d. 560 NE 9. Two vectors A and B are added together to form a vector C. The relationship between the magnitudes of the vectors is given by A + B = C. Which one of the following statements concerning these vectors is true? a. A and B must be displacements b. A and B must have equal lengths c. A and B must point in opposite directions d. A and B point in the same direction 10. Which expression is FALSE concerning the vectors are shown in the sketch? C B A a. C = A + B b. C + A = -B c. A + B + C = 0 d. C A + B 11. How to add vectors graphically? a. put them in line c. put them tip to tip b. put them tail to tail d. put them tip to tail 12. Which of the following is the definition of vector? a. a quantity that has only magnitude b. a quantity that has both magnitude and direction. c. a quantity that has only one direction d. a quantity that has magnitude but may or may not have direction 13. Which of the following answer contains two scalar quantities and one vector quantity? a. mass, displacement, time c. temperature, displacement, force 19 b. momentum, velocity, acceleration d. time, length, mass 14. A boy walks far 5km along a direction 530 West of North. Which of the following journeys would result in the same displacement? 15. a. 4km N, 3 km W c. 3 km N, 2 km W b. 4 km W, 3 km W d. 3 km N, 4 km W Which procedure should NOT be considered in finding the resultant vector graphically? a. use component method c. use ruler and protractor b. use head to tail method d. use scale Additional Activities 20 A. Draw each of the following vectors to scale. Indicate the scale that you have used. Use graphing paper, pencil, pen, ruler and protractor. 1. 12 km south 2. 1.5 m N 450 W 3. 1 m/s 200 E of N 4. 50 km/h 5. 5 mm B. Harold walks to school by walking 600 m Northeast and then 500 m N 40° W. Determine his resultant displacement by using accurate scale drawings. C. A frog is trying to cross a river. It swims at 3 m/s in a northerly direction towards the opposite bank. The water is flowing in a westerly direction at 5 m/s. Find the frog's resultant velocity by using appropriate calculations. Include a rough sketch of the situation in your answer. D. Adrianne walks to the shop by walking 500 m Northwest and then 400 m N 30° Determine her resultant displacement by doing appropriate calculations. Answer Key 21 What I Know B 22 What's More Activity 1 Assessment B 1. scalar D C D 2. vector 3. vector C 4. scalar D B D 5. scalar 6. vector B 7. vector C C C 8. scalar 9. scalar C 10. vector B C Activity 2 1. 30 m/s 450 N of E B C 2. 30 m/s 450 S of E C D 3. 30 m/s 200 S of E 4. 30 m/s 200 S of W C D Activity 4 B A 1. 80.78 cm 980 N of W 2. 4.92 cm 200 S of E B A D References Tabujara Jr., Geronimo D. K-12 Compliant Worktext for Senior High School General Physics 1. Manila, Philippines: JFS Publishing Services 23 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: blr.lrqad@deped.gov.ph * blr.lrpd@deped.gov.ph