Jace Science Reviewer 20250125 PDF

**Friction** - Friction opposes motion. - It cause the object that moves along a surface to slow down and eventually stop. - Is a force that opposes motion between two surfaces sticking or touching together. - Works on Surfaces of any object - Is a force that resists or opposes t...

**Friction** - Friction opposes motion. - It cause the object that moves along a surface to slow down and eventually stop. - Is a force that opposes motion between two surfaces sticking or touching together. - Works on Surfaces of any object - Is a force that resists or opposes the relative sliding movement of surfaces in contact with one another. **Air Friction** - affects the motion of falling objects by acting against the force of gravity. Examples: 1. Friction occurs between the tires and the road 2. Air Friction affects the falling objects 3. Friction occurs between the floor ad the floeet of the table and chairs **[Kinds of Frictions]** A. **Rolling Frictions -** When an object rolls over a surface, rolling friction is produced. Example: a. B. **Sliding Friction** - also called as dry friction, occurs when two object rub against each other or slide against each other. Sliding Friction caused by bonding between surfaces. Examples: b. c. C. **Fluid Friction** - is friction between moving objects and a fluid which can either be liquid or gas. Examples: d. e. f. D. **Static Friction** - Occurs in the stationary objects or objects at rest. It's a kind of friction that prevents an object from moving against a surface. Examples: g. **[Effects of Friction]** A. **Desirable Effects** a. b. c. B. **Undesirable Effects** d. e. **Ways to overcome or Reduce Friction** 1. Applying lubricants to a surface 2. Reducing the contact between moving surfaces 3. Minimizing the contact between rough surfaces 4. Using aerodynamic shapes Unit Test 1: 1. Which has the greatest friction? Answer: Wet Floor 2. The boat sailing at sea slow down. What kind of Friction is acting on it? Answer: Fluid Friction 3. Describe friction? It is a force that occurs when surfaces touch each other 4. How can you reduce friction between the feet of the furniture and the floor? Answer: By putting wheels or rollers on the feet of the furniture. 5. Which shows that friction is undesirable? Pushing furniture Types of Energy A. Potential Energy - is stored energy and the energy of position. Common examples of this type of energy are a ball held above the ground, a stretched rubber band in a slingshot, and a boulder on a hill. Potential Energy Forms: 1. 2. 3. a. b. c. 4. B. Kinetic Energy - is energy in motion. Examples: Stone released by a slingshot and a ball rolling on the ground. Kinetic Energy Forms 1. 2. 3. 4. a. b. 5. Unit Test 1. All potential energies can be changed into what type of energy? Answer: Kinetic Energy 2. What will always happen to two objects with the same charge? Answer: push away from each other 3. What form of energy is stored in the leaves of plants? Answer: Chemical Energy 4. A boy threw a ball over the fence. What energy did the moving ball have? Answer: Kinetic Energy 5. Cooking food in the microwave oven? Heat Energy 6. Making a tape recorder work? Sound Energy 7. Keeping a battery-operated clock working? Chemical Energy 8. Drying of Cloths? Light Energy 9. Lighting of a bulb? Light Energy 10. Keeping a candle lighted? Heat Energy 11. Keeping the bicycle moving? Chemical Energy 12. Grilling a barbeque? Heat Energy 13. Making a sewing machine work? Electrical energy 14. Keeping an electric fan working? Electrical energy 15. Burning Coal? Chemical Energy 16. Batteries placed in a toy car? Chemical Energy 17. Lighting striking the earth? Electrical Energy 18. A dancing boy? Mechanical Energy 19. The sun shining? Light Energy Transformation of Energy Law of Conservation of Energy - It's a guiding principle in energy transformation that states that energy cannot be created or destroyed but can be converted from one form to another. Riding a a bike is an illustration of the law of conservation of energy. When you stop pedaling on a flat path, the bike will eventually stop. The moving bike had kinetic energy. When you stop pedaling, the bike slowed down and eventually stopped because of frictional force. Unit Test 1. Energy is changed from one form to another form for it to be usable. This is called as? transformation of energy 2. The \_\_\_\_\_\_\_\_ of the sun is converted into chemical energy during the photosynthetic process? Answer: Light energy 3. The \_\_\_\_\_\_ of food turned into mechanical energy of the muscles when a person works? Chemical Energy 4. During energy transformation, \_\_\_\_\_\_\_ is always produced. Answer: Heat/Thermal Energy 5. Whenever a wind turbines moves, it produces mechanical energy that is then converted to \_\_\_\_\_\_\_\_\_ for people to use. Answer: Electrical Energy Simple Machines - Are simple tools that multiply the amount of force to make work easier. Compound Machines - consists of two or more simple machines. Examples: bicycle and sewing machines. Kinds of Simple Machines 1. Inclined Plane - is a simple machine that has a sloping surface. It lessen effort exerted over a distance. The inclined plane is a flat, supporting surface tilted at an angle with one end higher than the other. It's use in raising and lowering the load.  2. Lever - is a device that has a fulcrum or a pivot point, the effort where the force is applied, and the resistance and where the load is located. It compose of a straight or bent rigid bar that is free to turn on the fixed movable part known as fulcrum. Parts of lever: a. b. c. d. e. Classes of lever: a.  b. c.  3. Wedge - is a double-inclined plane that is sharpened to an end. It adds more force to the effort as it goes through a longer distance 4. Screw - is a form of inclined plane that is wrapped around a central shaft 5. Pulley - is modified wheel and axle. It is a special type of wheel that has a rope sliding on the groove of the wheel. The groove or events the rope from sliding. Kinds of pulley: a. b. c. 6. Wheel and axle - has the same appearance as a pulley but has a wheel that is fixed to the axle like in the steering wheel of a car. Unit Test 1. Ramp, Slope = Inclined Plane 2. Axe, Blade = Wedge 3. Wheel Barrow, Bottle Opener = Lever 4. Bicycle gears, door knob = Wheel and axle 5. Flagpole - Pulley 1. Baseball Bat = Third Class 2. Can Opener = Second Class 3. Broom = Third Class 4. Crowbar = First Class 5. Rake = Third Class 6. Oars = First Class 7. Wheelborrow = Second Class 8. Hammer = Third Class 9. Nutcracker = Second Class 10. Tweezer = Third Class 1. Uses wheels and a rope to raise, lower or move a load = Pulley 2. Made of two inclined planes that used to push objects apart = Lever 3. A rod balanced on a fixed point that can help lift a heavy weight with less effort = Lever 4. Any slope or ramp that makes it easier to lift something=inclined plane 5. A variation of the inclined plane that is wrapped around a cyclinder=screw