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- 1. Unit 1 Motion Lesson 1 Thenature of force
- 2. FORCE AND MOTION ïBalancedand Unbalanced Forces ïVelocity and Acceleration
- 4. Motion âą What ismotion? âą A change in the position of an object over time.
- 5. Overview âą Galileo wassuccessful in providing an experimental and theoretical background on how to describe motion. âą Newton who answered and explained why objects move and why they accelerate. âą Newtonâs Laws of Motion
- 6. âą What causesan object to move? - A force âą What is force? - Is define as a push or pull acting upon an object.
- 7. Example: 1. A gameof tug-of-war wherein two opposing teams are pulling on the ropes. 2. Pushing a cart at the supermarket.
- 8. Aside from seeingforce as simple push and pull, force can be viewed as any influence capable of producing a change in the state of motion. âą How do you know if something is in motion or has moved? âą What changes can force do to motion?
- 9. 1. Force canmake an object moved starting from rest position. 2. Force can make a moving object stop. 3. Force can change the direction of a moving object.
- 10. âą Whenever anobject moves from a rest position, its velocity increases. âą If it stops, then its velocity decreases. âą When it changes direction the velocity also changes.
- 11. âą A changein the state of motion means change in velocity. âą Whenever velocity changes with respect to time, acceleration produced. âą A change in state of motion means a change in velocity or simply the occurrence of acceleration.
- 12. âą Velocity, acceleration,and force are vector quantities. âą It must have magnitude and direction. âą Force is a quantity which is measured using a standard metric unit known as â newton (N)â.
- 13. âą 1 newtonis the amount of force required to give 1-kg mass an acceleration of 1 m/sÂČ. âą 1N = 1 kg m/sÂČ
- 14. âą A forcemay not always cause an object to move, especially if there is more than one force. âą What will happen if there is a presence of another force?
- 15. âą The presenceof another force may cancel the effect of the other force; causing no change in the state of motion of an object. âą If a single force is present, it can cause a change in the state of motion.
- 16. âą Single forcethat acts and causes a change in the state of motion of an object is known as the net force or the resultant force. âą The resultant force is the vector sum of all the forces acting on an object.
- 17. âą Several forcescan be combined or added to produce a single force- net force. âą A net force of zero indicates that all the forces cancel each otherâs effect.
- 18. + = 1 2 3 + = = +0 2 forces can combine so they add together(1), or subtract from each other (2). They may also cancel each other(3).
- 19. âą If nochanges in the state of motion is produced, these forces are said to be BALANCED FORCE. âą If there is a net force, then this force is said to be the UNBALANCED FORCE.
- 20. Types of Forces âąForces can be classified into two basic types based on how they are applied or how they act on the other objects. âą Contact forces âą Non-contact forces or action-at-a distance force.
- 21. Contact Forces 1. AppliedForce đčđđđ - force applied to an object by another object or person. - the direction of the force applied depends on how the force is applied.
- 22. 2. Normal Force(N) - support force exerted upon an object that is in contact with another object. - referred as pressing force. - always directed toward the pressing object and acts perpendicularly to the surface of the object.
- 23. 3. Frictional Force(f) - force exerted by the surfaces in contact with each other and move relatively being pressed with each other. - friction opposed the motion.
- 24. - results whentwo surfaces are pressed together closely, causing attractive intermolecular forces bet. The molecules of the 2 diff. surfaces. -can be calculated using equation : f=ΌN, where Ό is the coefficient of friction and N is the normal force.
- 25. 4. Air ResistanceForce (Fair) - is a special type of frictional force that acts on objects as they travel through the air. - always opposes the motion of the moving object. - it is most noticeable in objects that travel at high speed or in objects with large surface areas.
- 27. 5. Tensional Force(T) - is the force which is transmitted through a string, rope, or wire when it is pulled tight by forces acting at each end.
- 28. 6. Spring Force(đčđ đđđđđ) - force exerted by a compressed or stretched spring on any object that is attached to the spring.
- 29. Non- Contact Forces 1.Force of Gravity (also Known as Weight, W) - force with which the Earth, moon, or massive body attracts an object toward itself.
- 30. - this isthe weight of an object. - force on an object on Earth is always equal to the weight of the object as given by the equation W=Mg, where g is the acceleration and due to gravity which has a value of 9.8 m/sÂČ( on Earth) and m is the objectâs mass (in kg) .
- 31. 2. Electrical Force -this is the force that exist between charges. It can either be attractive or repulsive force. 3. Magnetic Force - this is the force that exist in magnets. It is the force that makes magnets attract or repel objects or other magnets.
- 32. Free-Body Diagram FBD -forces can be seen based on how they act on an object. - forces acting on an object can be shown by representing them as arrows. - this representation is called a Free- Body Diagram (FBD).
- 33. When constructing FBDâs,the following assumptions are made: 1. Pulleys are assumed frictionless; 2. Pulleys are assumed weightless; 3. Ropes, cables, cords, and wires are assumed weightless.
- 34. In constructing FBD,one frees the body (or object) from its environment and draws the body indicating the magnitudes and direction of all forces acting on the body.