8 Science Quarter 1 – Module 1: Forces and Motion A Requirement for EDUC403 Educational Technology and Instructional Material Development MA in Educational Management Science – Grade 8 Quarter 1 – Module 1: Forces and Motion First Edition, 2020 This module is crafted as a requirement for the subject 403, Educational Technology and Instructional Material Development, for MA in Educational Management. In accordance to Republic Act 8293, section 176, no parts of this module will be used without the consent of the author or without proper citation. You may contact the author if you intend to use any part of this material. Development Team of the Module Author: Jenny Grace C. Capuno Editor: Cristina S. Magpantay Reviewer: Jesse M. Geron Layout Artist: Jenny Grace C. Capuno Proofreader: Harold I. Inciong 8 Science Quarter 1 – Module 1: Forces and Motion Introductory Message For the facilitator: This module is designed as supplemental material for understanding the relationship between forces and motion. This contains activity sheets and will be used to evaluate student’s learning competencies. Instruct learners to use separate sheets in answering the pre-test, self-check exercises, and post-test. Accomplished activities and exercises will be submitted to the subject teacher on or before the given schedule. It should also be noted that parents should monitor the progress of their child’s learning. For the learner: This module is designed to guide in understanding the concepts of force and motion. All parts of this module are important, so make time to read everything for you to easily answer the activities. Make sure that you write your answer in your quiz notebook and submit it on or before the due date. Do not leave unanswered activities. If you have questions and clarifications, communicate with your subject teacher. Good luck and enjoy learning! What I Need to Know This module is designed to help you master the concepts of Force and Motion. The scope of this module allows you to use it in many different learning situations. This learning material provides you with an overview of forces that will lead to a better understanding of: Lesson 1 – Three Laws of Motion After exploring this module, you are expected to: 1. understand the concept of force and it’s relation to motion 2. differentiate balanced and unbalanced forces 3. infer the relationship between the amount of force applied and the mass of the object to the amount of change in the object’s motion. 4. recognize the different laws of motion in everyday activities 5. summarize learnings about the three laws of motion. What I Know Choose the letter of the best answer. Write the letter on a separate sheet of paper. 1. A book is resting on your table. Which statements below best describe the situation? a. No forces acting on the book. b. Your book pushes on the table only. c. The table pushes on your book only d. The forces acting on the book are balanced. 2. Which force always pulls downward on objects? a. Friction force b. Applied force c. Gravity d. Air resistance 3. A change to the motion of an object is caused by _____. a. Balanced forces b. Unbalanced forces c. Acceleration d. Velocity 4. Which of the following is an example of unbalanced force. a. an arm wrestling where there is no winner b. a tug of war where the rope doesn’t move. c. a girl sitting on a chair. d. a boy pushing a cart. 5. Two students are pushing a table in opposite direction. Student A exerts 15N force to the right, while student B applies 25N force to the left. Which direction will the box move? a. upward b. downward c. to the left d. to the right 6. According to the first law of motion, why is it important to wear seatbelt when traveling in vehicles? a. It acts as an unbalance force that will stop you from being in motion. b. It stops vehicular accidents. c. It is required by law. d. It makes you comfortable when sleeping while traveling. 7. What happens to acceleration of an object if you increase the mass? a. the acceleration increases b. the acceleration decreases c. the acceleration will remain the same d. the object will stop 8. Two grocery shoppers are pushing two carts with 10 kg of items each. Shopper A exerts for of 15 N, while shopper B exerts 10 N. Which of them will reach the counter first? a. Shopper A b. Shopper B c. both Shoppers A and B d. neither Shopper A nor B 9. A boy pushing 10 kg box is accelerating at 5 m/s2. How much force is need to push the cart? a. 2 N b. 4 N c. 6 N d. 8 N 10. Which law of motion states that for every action, there is equal and opposite reaction? a. Law of Inertia b. Law of Acceleration c. Law of Action-reaction d. Law of Gravity LESSON 1 NEWTON’S THREE LAWS OF MOTION In this lesson, you will differentiate the three laws of motion and how they affect the motion of an object. You will also get familiar with the vocabulary terms associated in this lesson. What’s In In Grade 7, you learned about motion in terms of displacement, speed, velocity, and acceleration. Most motions that we encounter in our daily activities are caused by FORCE. This module will teach you the effects of force on motion. Notes to the Teacher Provide students with an overview by discussing the different types of forces. Students must have a clear understanding of forces acting on objects before proceeding to the main concept. What’s New What is force? Force is defined as push or pull acted on an object. There are two classifications of forces: contact force and non-contact force. Contact forces are forces which involve two objects physically interact or touch each other. Non-contact forces are forces that act between two objects that do not require physical interaction. Types of forces The table below explain and illustrate the different types of forces. CONTACT FORCES EXAMPLE ILLUSTRATION 1. Air-resistance force The force acting on objects traveling on air. 2. Tension force The force transmitted along a string, cable, rope, or a wire when pulled by an object to the opposite side of the string. 3. Spring force The force exerted by a stretched or compressed spring on an object that is attached to it. 4. Normal force (reaction) When one force is exerted on another body (A), the second body (B) exerts force perpendicular to the surface of the first body (A). 5. Applied force The force exerted by an object or a person (A) to another object (B) by physical contact. Normal force acting on the vase (A) Normal force acting on the table (B) 6. Friction force The force that resists the sliding or rolling of one object (A) over the other (B). NON-CONTACT FORCES EXAMPLE ILLUSTRATION 1. Gravitational force The force that attracts any object with mass. Fgrav = m * g Where: g = 9.8 N/kg (on Earth) and m = mass (in kg) 2. Electrical force The force exerted between two charged dies. 3. Magnetic force The force of attraction or repulsion between electrically charged particles due to motion. What Is It Sir Isaac Newton was one of the most prominent scientists of all time. His ideas became the foundation for modern physics. During the summer of 1665 and the spring of 1667, Isaac Newton made two long trips to his hometown, Woolsthorpe, to escape the plague spreading in Cambridge. The bubonic ‘Great Plague’ of 1665–1966 was the worst epidemic in England after the black death of 1348. By 1666, Newton had submitted the blueprints for his three laws of motion. After twenty years, he presented his three laws of motion in the book, "Principia Mathematica Philosophiae Naturalis." NEWTON’S FIRST LAW OF MOTION The Law of Inertia states that: An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon an external force. To illustrate: It means that the object keeps doing what it does. This tendency is called inertia. Inertia is the tendency of an object to resist change in its state of motion. Galileo discovered the concept of inertia in the seventeenth century. Based on his experiment, if there is no inertia, an object will move in constant speed. Remember: The bigger the object has a greater tendency to resist changes in its state of motion. Between a golf ball and a bowling ball, bowling ball is more difficult to move. The motion of an object may be caused by two kinds of forces: Balanced and unbalanced forces. The table below explain the two forces briefly. BALANCED FORCE - Equal in magnitude - Opposite direction - Causes no change in the speed of the object UNBALANCED FORCE - Unequal in magnitude - Can be in any direction, but opposite - Causes change in speed and direction Examples: Examples: Net force is the sum of all forces acting on an object. If net force is equal to zero (F net = 0), the force is balanced, therefore, objects will not move. NEWTON’S SECOND LAW OF MOTION The Law of Acceleration states that: The acceleration of an object is directly proportional to the magnitude of the net force acting on it and inversely proportional to its mass. This means that the acceleration is always in the same direction as the net force. This is express mathematically as Fnet = ma. This means: Objects with lighter mass will accelerate more than the heavier mass. More force moving an object, the more the object will accelerate. If force is increased, acceleration increases. If mass is increased, acceleration decreases. CALCULATING SECOND LAW OF MOTION Newton’s second law is best described with a mathematical equation that relates three variables, force, acceleration and mass to one another. The equation can be stated in three forms: F=mxa m=F/a a=F/m Mass is defined is the quantitative measure of inertia, a fundamental property of all matter. Acceleration on the other hand, is the rate of change of the velocity of an object with respect to time. The unit of force is Newton (N); mass is kilogram (kg); acceleration is meter per second squared (m/s2) Example #1: A 2 kg object accelerated at a constant 5 m/s2. How much force is needed to accelerate the object? Given: Required: Equation: Solution: Answer: 2 kg, 5 m/s2 Force F=mxa F = 2kg x 5 m/s2 F = 10 kg/m/s2 or 10 N Example #2: A 10 N force is applied to an object with a mass of 2 kg. What the acceleration of the object? Given: Required: Equation: Solution: Answer: 10 N, 2kg Acceleration a = f/m a = 10 N / 2kg a = 5 m/s2 NEWTON’S THIRD LAW OF MOTION The Law of Action-Reaction states that: For every action, there is an equal and opposite reaction. This means that: In every interaction, there is a pair of forces acting on the two interacting objects in different directions. The size of the forces on the first object equals the size of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs. Action and reaction acts on different bodies. Examples: A variety of action-reaction force pairs are observed in our environment. Think about the fish swimming through the water. A fish uses its fins to push water backwards. But a push on the water will just make the fish accelerate. Below are other examples. What’s More Experiment #1: Egg Drop Objective: At the end of this activity, students will be able to understand how inertia works. Materials Needed: Glass with water Boiled egg Cardboard (thick) Toilet paper cardboard Procedure: 1. Place the cardboard on top of the glass 2. Place toilet paper roll vertically in the middle of the cardboard 3. Balance egg on top of the toilet paper roll so the egg is lying on its side. See the picture. 4. Once everything is balanced on top of each other, with one swift and quick motion hit the side of the cardboard with your hand. Put enough force to push the cardboard off the glass. Q1. What happens the egg? Q2: How does inertia work on this experiment? Q3. In your activity notebook, draw the outcome of the experiment. (5 points) Experiment #2: Toy Truck Experiment Objective: At the end of this activity, students will be able to understand relationship of mass and acceleration. Materials Needed: Toy truck (dump truck) Small rock (same size and weight) Ramp Meter stick, ruler or tape measure Stop watch Procedure: 1. Construct a simple ramp 18 inches high and about 24 inches long using a piece of thick cardboard. 2. Place a toy truck at the top of the ramp. 3. Release it and measure how far it rolls. 4. Put three pieces of small rocks. 5. Release the toy truck and measure how far it goes. Record your distance and time observation. 6. Repeat the experiment with six rocks, then nine rocks. Q1. What happens to the acceleration of the truck when you increase the rocks? Q2: What is the relationship of mass to the acceleration of an object? Q3: Which attempt has the longest distance? Why? Record your observation in your activity notevook. No. of Attempts 1 2 3 Distance (meters) Time (seconds) Experiment #3: Balloon and Rockets Objective: At the end of this activity, students will be able to understand the third law of motion by assimilating the action of a balloon to a rocket. Materials Needed: Balloons 5 m. string Tape Straw Procedure: 1. Insert one end of the string through the straw. 2. Tie the string to stationary (still) objects on opposite sides of the room. Make sure to stretch the string tight. 3. Blow up the balloon and hold it tight. Air should not escape but don’t tie it. 4. Ask someone hold the balloon under the straw and tape the balloon to the straw in two places. 5. Let go of the balloon and observe as it propel like a rocket. Q1. What happens when you let go of the balloon? Q2: What are the forces acting on the balloon? Q3: Identify the action and reaction acting on the balloon. In you activity notebook, draw the activity and use arrow representing action and reaction (5 points). What I Have Learned 1. Forces acting on an object may be contact and non-contact force. 2. When a balanced force acted on an object, it causes no change in the object’s motion. When an unbalanced force is acted on an object, it will move, change in speed, or direction. 3. It was Galileo who pioneered the concept of inertia, while Sir Isaac Newton formulated the laws of motion. 4. Newton’s three laws of motions are Law of Inertia, Law of Acceleration and Law of Action-reaction, respectively. 5. According to Law of Inertia, the greater the mass of an object, the higher the inertia. 6. Law of acceleration s mathematically expressed as F = mxa. The acceleration of an object depends directly upon the net applied on the object, and inversely proportional to the mass of the object. 7. If the force applied on an object is increased, the acceleration of the object is increased. If the mass of an object is increased, the acceleration of the object is decreased. 8. According to Law of Action-reaction, the magnitude of the forces applied on the first object equals the magnitude of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. 9. The concept of the three laws of motion can be summarized through this diagram: Diagram adapted from https://www.sas.upenn.edu/~kennethp/nkdievid2.pdf What I Can Do Activity 1. Understanding Science Words Learning the Skill: Solving Crossword Puzzle Directions: Identify the word using the clues provided. Activity 2. Concept Check Directions: Study the concepts of three laws of motion, then answer the following questions. 1. Which law is associated with inertia? ____________________________________________________________ 2. What will happen to the acceleration if you increase the force applied to the object? ____________________________________________________________ 3. What will happen to the acceleration if you apply the same force to an object with lesser mass? ____________________________________________________________ 4. Which law states that force is dependent on the object’s mass and acceleration? ____________________________________________________________ 5. Which law is also known as the action-reaction? ___________________________________________________________ 6. If the forces are balanced, what are the resulting acceleration? ___________________________________________________________ 7. What is the net force if you push a table to the left with 10N of force and a friend pushes the table to the right with 10N of force? ___________________________________________________________ 8. What is the net force if you start to pull instead of pushing in #7? ____________________________________________________________ 9. What will happen to the acceleration if you double the mass of an object while leaving the net force the same? _____________________________________________________________ 10. A Toyota Grandia with a mass of 2,200 kg exerts 2500 N. What is the van’s acceleration? _____________________________________________________________ Additional Activities Activity 3: Inertia and Moving Objects Consider a man driving with a cup filled with coffee on his side. As he accelerates, the cup of coffee moves to the same direction with the car. When driver suddenly hits the break, the coffee continues to move forward. Because of sudden change in motion, the coffee spills. With this concept in mind, answer the following questions in your activity notebook. 1. What happens to the driver’s motion while the car is running? 2. What will happen to driver’s motion if the man suddenly steps the break? 3. Why is it important to wear a seatbelt when traveling on a vehicle? 4. What does the law of inertia state? Activity 4: Mass and Acceleration Suppose a jeep and a tricycle traveling from opposite directions collide with each other. Both accelerate at the same speed. Anticipate the outcome of the scenario and answer the following questions? 1. Which vehicle do you think will be thrown farther? 2. Which vehicle has greater mass? 3. What is the relationship between the mass and motion of an object? 4. Based on the concept of mass and acceleration, which one will acceleration faster. 5. What is the relationship of mass and force and their effect to motion? 6. Calculate the force required to move an 86 kg tricycle to 5.5 m/s acceleration. Activity 5: Action-Reaction Observe how the law of motion acting on clothes hanging on the clothes line. Answer the questions below. 1. Which Newton’s law of motion is displayed in the picture? 2. What are action and reaction forces acting on them? 3. Why do you think clothes are not falling or touching the ground? 4. Does the example shows a balanced or unbalanced force? 5. What does the third law of motion state? Activity 5: Forces and Motion Daily Directions: The examples show forces and motion in our daily activities. In the first column, identify if the force acting on an object is BALANCED or UNBALANCED. Write N/A if the statement does not show any of them. In the second column, determine the law of motion stated. Write FIRST, SECOND or THIRD on the space provided. ACTIVITIES 1. Exerting force to raise the flag on a pole. 2. A driver of a bus, hit the brake suddenly and, by inertia, shoots forward because he’s not wearing a seatbelt 3. A rolling ball does not stop moving by itself. 4. The hammer strikes a nail, and the nail goes deeper into the wood. The hammer makes a backward movement when it hits the nail hard. 5. A book on a table is in a state of rest. 6. When rowing a boat, the water is pushed backward with the paddle and the reacts by pushing the boat in its opposite direction. 7. When two people pull the opposite sides of the same rope, and it stays at the same point, 8. A golfer must exert force in order for his ball to hit the hole. 9. A rocket needs to acquire a certain speed in order to be able to go into orbit. 10. The calculation of the force required to push a box. BALANCED OR UNBALANCED FIRST, SECOND, THIRD Assessment I. Choose the letter of the best answer. Write the letter on a separate sheet of paper. 11. Which statements below best describe the forces acting on a book resting on a table? a. Your book pushes on the table only. b. The table pushes on your book only c. The forces acting on the book are balanced. d. No forces acting on the book. 12. Which force always pulls downward on objects? a. Friction force b. Applied force c. Gravity d. Air resistance 13. A change to the motion of an object is caused by _____. a. Velocity b. Balanced forces c. Unbalanced forces d. Acceleration 14. Which of the following is an example of unbalanced force. a. an arm wrestling where there is no winner b. a tug of war where the rope doesn’t move. c. a girl sitting on a chair. d. a boy pushing a cart. 15. Two students are pushing a table in opposite direction. Student A exerts 25N force pull to the left, while student B applies 15N force push to the left. Which direction will the box move? a. to the left b. to the right c. upward d. downward 16. According to the first law of motion, why is it important to wear seatbelt when traveling in vehicles? a. It acts as an unbalance force that will stop you from being in motion. b. It stops vehicular accidents. c. It is required by law. d. It makes you comfortable when sleeping while traveling. 17. What happens to acceleration of an object if you decrease the mass? a. the acceleration increases b. the acceleration decreases c. the acceleration will remain the same d. the object will stop 18. Two grocery shoppers are pushing two carts with 10 kg of items each. Shopper A exerts for of 15 N, while shopper B exerts 10 N. Which of them will reach the counter first? a. Shopper A b. Shopper B c. both Shoppers A and B d. neither Shopper A nor B 19. A horse 10 kg cart is accelerating at 25 m/s2. How much force is need to push the cart? a. 150 N b. 250 N c. 350 N d. 450 N 20. Which law of motion states that for every action, there is equal and opposite reaction? a. Law of Gravity b. Law of Inertia c. Law of Acceleration d. Law of Action-reaction II. Summarize the concept of Three Laws of Motion. Choose from ANY of the following output. (20 points) a. Write an essay with ten (10) or more sentences. b. Illustrate the concepts of motion by using graphic organizers. c. Create a poster featuring the three laws of motion. d. Record a vlog about the summary concepts of motion. Video must be less than 3 minutes. RUBRIC Creativity 5 Content 10 Organization 5 Answer Key What I Know 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. D C B D C A B B A C Assessment 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. C C C D A A A B B D What's More Activity #1 Across 1. Motion 3. Air resistance 4. First Law 5. Magnetic 7. Applied 11. Friction Activity #2 1. First Law 2. Acceleration will increase 3. Acceleration will increase 4. Second Law 5. Third Law 6. Zero 7. Zero 8. The Net force will be 20N. The table will move to the left 9. The acceleration will decrease 10. Acceleration: 1.1364 m/s2 Additional Activities Experiment #1 1. The egg falls into the water. 2. Inertial keeps the egg on top of the cardboard roll. 3. Draw answer #1 Experiment #2 1. Acceleration decreases 2. The greater the mass, the lesser the acceleration 3. First Experiment #3 1. The balloon propels to the opposite side. 2. Applied force and air resistance 3. Action: the balloon releases air, Reaction: the balloon propels forward Activity #3 1. 2. 3. The driver’s motion goes along with the car. The driver will continue to move forward. The belt acts an unbalanced force that keeps the driver from being in motion. 4. The object in motion will remain in motion and an object at rest will stay at rest unless acted by an unbalanced force. Activity #4 1. 2. 3. The tricycle will be thrown farther The jeep Mass is inversely proportional to acceleration. Meaning, more mass = less acceleration = less motion 4. The tricycle 5. If the force applied is greater, the acceleration of the object with less mass will increase. 6. 15.6 N Activity #5 1. 2. 3. 4. 5. Law of action-reaction Gravity and tension force The tension force keeps the clothes on their place. The force applied by cloth pins work, too. Balanced force For every action, there’s an equal and opposite reaction. References Admin. "Balanced Force : Definition, Examples, Unbalanced Force." BYJUS. July 22, 2020. https://byjus.com/physics/balanced-force/. Admin, Sumit Bhardwaj Says:, Eyop Love Says:, and Look Says:. "Newton's Third Law of Motion Examples in Everyday Life." Physicsabout. July 11, 2020. https://physicsabout.com/newtons-3rd-law/#:~:text=Newton's 3rd law of motion states that action and rea. "Egg Drop." Science Fun. https://www.sciencefun.org/kidszone/experiments/eggdrop/#:~:text=How it Works:,into the glass of water. "Mechanics: Physics Aboout." Physicsabout. https://physicsabout.com/category/mechanics/. "Newton's Laws of Motion Tutorial." The Physics Classroom. https://www.physicsclassroom.com/Physics-Tutorial/Newton-s-Laws. “Newton's Laws of Motion.” Reading, n.d. https://www.sas.upenn.edu/~kennethp/nkdievid2.pdf. Schnotz, Wilhelm. "Second Law of Motion Experiments." Sciencing. March 02, 2019. https://sciencing.com/second-law-motion-experiments-6952612.html. "Year of Wonders 1665-1667." National Trust. https://www.nationaltrust.org.uk/woolsthorpemanor/features/year-of-wonders#:~:text=Whilst escaping the Great Plague,the “Year of Wonders'.&text=Between the summer of 1665,escape the plague affecting Cambridge.
