The document discusses the concepts of force, pressure, and friction. It defines force as a push or pull and describes several examples. It also explains how forces can change the speed, direction, or shape of an object. The document addresses some common misconceptions people have about these concepts and provides explanations to clarify them. It concludes by discussing the relationship between force and pressure and giving some examples of friction.

1. FORCE AND PRESSURE

2. RELATIONSHIP BETWEEN FORCE AND PRESSURE FRICTION EFFECTS OF FORCE INTRODUCTION FORCE

4. Pressing the switch Kicking a ball Launching rocket Pushing trolley Knocking a nail

5. Tug-of-war Raising a flag Pulling a box Opening the door Drawing back a bow

6. Rowing a boat Scrubbing the floor Sawing wood Playing guitar

7. Stops a moving object or makes a stationary object moves Change the speed of a moving object Change the direction of a moving object Changes the shape permanently Changes the shape temporarily EFFECTS OF A FORCE

8. Stretch a rubber band After An object that will return to its original shape and size after being squeezed, pressed, twisted and stretched is elastic After After Press a sponge Squeeze a spring

9. Drop a glass After After Tear a piece of paper After Crush an empty can An object that will not return to its original shape and size after being squeezed, pressed, twisted and stretched is inelastic MISCONCEPTION???

10. A solid cannot be compressed or stretched!! CHILDREN’S MISCONCEPTION EXPLANATION The shape of a solid object changes when a force is applied to it whether it’s temporarily or permanently Example: crushing a can – changes the shape permanently

11. when a force is applied in the opposite direction (or different direction), the moving object will change its moving direction MISCONCEPTION ???

12. Misconception? A force is needed to keep an object moving with a constant speed Explanation: You do not need forces to move at a steady speed but if you keep the same speed yet change direction, like a moon around a planet, then you have a force acting on you anyway An object will move faster when a force is applied It moves in the same direction as the applied force

14. Force is a property of an object. An object has force and when it runs out of force it stops moving EXPLANATION an object at rest or in motion will remain in that state unless an external force is applied to the object Newton 1 st Law

16. MISCONCEPTION??? Friction is only present when something is rubbing against a moving object EXPLANATION Occurs when two surfaces are moving in contact with each other

17. Examples of friction