Force and Interaction (PDF)

1.What is a door? 2.What is a door for? 3.As part of an area, what is usually done to a door? 4.What must be done for the door to either close or open? Pre – Learning Check 1. Give examples of forces you encounter in everyday life. 2. How do we measure the strength of a force? 3. What is...

1.What is a door? 2.What is a door for? 3.As part of an area, what is usually done to a door? 4.What must be done for the door to either close or open? Pre – Learning Check 1. Give examples of forces you encounter in everyday life. 2. How do we measure the strength of a force? 3. What is the difference between balanced and unbalanced forces? Explain the impact of each on motion. Lesson 1: Force and Interaction Force- is essentially a push or a pull, capable of setting an object into motion or bringing it into a halt. Moreover, it can even change the shape of an object when applied. Concept Check!  Determine the effect of force in the different given situations or conditions.  A. Setting an object in motion  B. Bringing an object to a stop  C. Changing the shape of an object  Force and its role in other concepts Force plays a crucial role not only in the physical world, but also across various disciplines such as biology, chemistry and Earth Science. In chemistry, the way the substance dissolves in a given solvent is determined by the forces between the particles of solute and solvent. In biology, such as processes like mitosis and meiosis, forces come into play to ensure accurate separation of chromosomes to each daughter cell. In the next chapters, you will learn how forces in the Earth’s mantle propel the movement of tectonic plates, giving rise to different phenomena such as earthquakes, volcanic eruptions, and the formation of mountain ranges. Explain the following situations where forces are applied and predict the effect of the force(s) Force Vector Force Vector Physical quantities can be classified as either scalar or vector. Scalar quantity- characterized solely by magnitude Vector quantity – characterized by both magnitude and direction. Force is a vector quantity and is usually expressed in the SI unit, the Newton (N). As a vector, force is represented as a line with an arrowhead at its tip. The length of the arrow indicates the magnitude of the force, while the arrowhead tells its direction. Meanwhile, the four cardinal directions – north (N), south (S), east (E), and west (W)- are fundamental conventions employed in a Cartesian plane. Consequently, north and east signify positive directions, while south and west signify their negative counterparts. Northwest (NW), southwest (SW), northeast (NE), and southeast (SE)form angle of 45 degrees from the reference direction Mini test Instruction: Draw an accurate representation of the following forces using a scale (1 cm = 40 N) 1.20 N, East 2.100 N, West 3.120 N, Southeast 4.85 N, North 5.180 N, Northwest  Types of Force Contact Forces – exerted by direct physical contact between two objects  Normal force – the force exerted by a surface in contact with an object  Applied force – the force exerted directly on an object  Friction force – this force occurs when two surfaces are in contact and move past each other.  Tension force – the pulling force exerted by a stretched rope, string, or cable on attached object.  Types of Force  Spring/restoring force – the force present in springs, causing them to return to their original position after being stretched or compressed.  Air resistance – this force opposes the motion of an object moving through air.  Buoyant force – the upward force exerted by a fluid on a submerged object.  Types of Force Non -contact forces – a type of force that does not involve direct contact. It acts at a distance or field force  Gravitational force – this force is exerted by a massive object on another object.  Electromagnetic force – this force can either be attractive or repulsive and acts between charged bodies Mini test Instruction: Determine the forces involved in the various situations below. 1. Swinging a pendulum 2. Pushing a box on an inclined plane 3. A stone hung using a spring balance