Prepared by: Gemima B. Galvez
I. Learning Objectives
At the end of the lesson, 95% of the fourth year students should be able to: 1. define friction;
2. identify the types of friction;
3. draw the free body diagram of forces in a given problem; and 4. determine the advantages and disadvantages of frictional force in our daily life.
II. Learning Content
A. Subject matter
1. Content outline
Definition of terms
Types of friction
Construction of free-body diagrams
B. Science Concepts
1. Friction or frictional force (Ff or Ffr ) is the force between surfaces in contact that resist their relative motion. 2. Static friction is the type of friction that occurs between bodies in contact which is at rest. 3. Kinetic friction occurs between bodies in contact which is in sliding motion. 4. Rolling friction occurs between bodies in contact that are in rolling motion. 5. Weight is the force directed towards the center of the earth which is perpendicular to the horizontal ground or surface. 6. Applied force is the push or pull applied to any object. 7. Normal force is the force that equals the force of gravity to keep an object in the surface it is situated.
C. Science Process Skills
2. Identifying variables
D. Value Focus
2. Hard work
3. Valuing life
1. Beiser, Arthur, Modern Technical Physics-6th Edition, Wesley Publishing Company,1997 2. Silverio, Angelina, Physics; Exploring Life Through Science-2nd Edition, Phoenix Publishing House Inc., 2011 3. Navasa, Delia, Fourth Year Physics, Phoenix Publishing House Inc., 2011
F. Teaching Aids
2. Pentel Pen
III. Teaching Methodology
Teacher’s Activity| Students’ Activity| Time Frame|
A. PrayerPrayer and greetings.B. ReviewToday, we will have a new lesson, but before that let us first review some concepts related to our new topic.I have here some strips of paper containing questions. I will roam around and ask volunteers to pick and answer these questions.Very good.B. MotivationBefore we start our new lesson for today, let me show you a simple demonstration. We have here a table, I will apply a pushing force to it, so observe what will happen..Now, what have you observed?Why do you think the table did not move?What if I will apply greater force?Now, I will push the table with greater force, what do you think will happen?So why do we need to apply greater force so that the table will move?C. Presentation of the LessonTo further explain the relationship of the forces in my demonstration, today we will discuss fiction force, its types, and how this force affects our day to day activities.D. Lesson ProperBased on what you have observed a while ago, what do you think was the cause of the table’s impending motion? Then what is friction?Why do you think there is friction or frictional forces?So, do you think friction depends on the surfaces in contact?Definitely.Friction depends on the surfaces in contact. We have three types of friction force, namely static, kinetic and rolling friction.Now, I will show you some pictures depicting different situations involving friction.Based on the picture, what kind of friction force is involved?How can we define static friction?Vey good.In this picture, what kind of friction force is involved?How can we say that it is kinetic friction?That’s rightHow about this picture?How do we know that it is a rolling friction?Who can give other examples of the different types of friction?Now that we have identified the types of frictional forces, let us identify other forces acting on an object in a horizontal plane.Based on the illustration, who can identify the different forces acting on the object in the surface?What if we apply a...