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  1. 1. Friction Prepared by: Lovelyn M. Mataac Teacher
  2. 3. Friction <ul><li>F orce that opposes the motion of an object when the object is in contact with another object or surface. </li></ul><ul><li>Force that slows down or stops motion. </li></ul>
  3. 4. How FRICTION affects motion? <ul><li>if you roll a ball along the floor or ground, it will slow down and stop even though no apparent force is being applied to it. The ball slows down and stops because of friction. </li></ul><ul><li>Friction slows down a moving object. Friction occurs when two objects rub against each other. </li></ul>
  4. 5. <ul><li>A car that runs on a very rough road slows down due to friction. However, on a smooth road, it travels fast. </li></ul><ul><li>A smooth surface has a very few bumps and hollows. There is less friction on a smooth surface. A running object can glide or move continuously with very little force. </li></ul>
  5. 6. <ul><li>Smooth surface produces less friction and allows shoes and tires to slip. </li></ul><ul><li>On a rough surface, there are more bumps and hollows. When you push the cart on a rough road, it will travel slowly. There’s more friction acting on the moving cart. The rougher the surface, the more friction there is, thus, the slower an object moves. </li></ul>
  6. 7. <ul><li>Friction is lesser on a smooth, shiny surface. </li></ul><ul><li>Friction is greater on a rough surface. </li></ul>
  7. 8. Advantages and Disadvantages of Friction <ul><li>Advantages </li></ul><ul><ul><li>Friction enables belts to cling to pulleys and nails to hold objects together . </li></ul></ul>
  8. 9. <ul><li>A running car or bicycle uses friction to stop. As the driver steps on the brakes, the vehicle slows down to a full stop. This is possible because of the friction between the brakes and the wheels. </li></ul>
  9. 10. <ul><li>Walking, running, playing, writing, sitting, standing, or eating cannot be possible without friction. </li></ul>
  10. 12. Disadvantages of Friction <ul><li>Shoes, slippers, tires and anything that are used for moving become worn out. Friction produces heat that causes objects to wear out. </li></ul>
  11. 13. <ul><li>Friction makes work tedious. Because of the resistance, workers need to exert more effort and energy to accomplish their work to overcome resistance. </li></ul>
  12. 14. <ul><li>Some machines perform less efficiently and wear out faster with friction. </li></ul><ul><li>Friction also causes sparks, overheating, and machine breakdown. </li></ul><ul><li>Friction reduces speed. Even airplanes cannot fly as fast as they are able because of air friction. </li></ul><ul><li>Racing cars and other vehicles consume more energy to run fast and overcome the resistance of the roads. </li></ul>
  13. 15. <ul><li>Friction can also make speeding objects to tumble down and cause accidents. </li></ul>
  14. 16. Ways of reducing friction <ul><li>Smoothing out Surface </li></ul><ul><li>ex. Applying floor wax and scrubbing the floor. </li></ul><ul><li>Placing a slippery substances between two solid surfaces </li></ul><ul><li>ex. Grease, oil and other lubricating liquids </li></ul>
  15. 17. <ul><li>Using rotating objects </li></ul><ul><li>ex. Roller bearings, ball bearings and </li></ul><ul><li>wheels </li></ul>
  16. 18. <ul><li>Streamlining vehicles to reduce friction caused by air. </li></ul><ul><li>ex. Streamlined front of planes </li></ul>
  17. 19. Ways to increase friction <ul><li>New materials with more bumps and hollows are produce for making car brakes lining. </li></ul>
  18. 20. <ul><li>New styles for the soles of athletes’ shoes. Its aim is for runners to run with greater speed. </li></ul>
  19. 21. <ul><li>Write the letter of the best answer. </li></ul><ul><li>It is the force that slows down or stops motion. </li></ul><ul><li>a. Acceleration b. motion b. friction </li></ul><ul><li>2. Friction is always beneficial. </li></ul><ul><li>a. True b. false </li></ul><ul><li>Friction can be reduced. </li></ul><ul><li>a. True b. false </li></ul>
  20. 22. <ul><li>4. What is the effect of spikes on the shoes of a runner? </li></ul><ul><li>A. Increase his speed </li></ul><ul><li>B. Increase friction </li></ul><ul><li>C. all </li></ul><ul><li>5. How will you decrease friction? </li></ul><ul><li>A. Apply lubricant </li></ul><ul><li>B. Polish surface </li></ul><ul><li>C. all </li></ul>
  21. 23. Assignment: <ul><li>Bring the following tomorrow (by group) </li></ul><ul><li>1. cup </li></ul><ul><li>2. plastic ruler </li></ul><ul><li>3. nail (1, long) </li></ul>