Effects of force

The presentation is meant for middle school science students. It is appropriate for class 7 and 8 students

1. Physics : Grade 8 Learning episode-2 ~ Lalit kishore , plenum school, HP Effects of force

2. Force vs visible effects A force is felt/experienced by its 2 main effects. It causes ... Change in the state of motion and Change in shape or size In the case of a number of forces acting on an object,... Effects are produced by the net force Net force is also called the ‘resultant force’

3. Invisible effects of force At times, effects of force are not visible outwardly on the object, but are felt by the applier of the force In that situation,... the phrase ‘tends to change’ is used with the two effects Exactly, the force is defined as... The vector physical quantity that produces or tends to produce the change in the state of motion or shape is called force

4. Examples of the ‘force that tends to change’ A person pushing the wall: Wall does not move but applied force is felt by the muscles of the person A car stuck in mud A heavy barrier not moved by a vehicle A person trying to stop a moving railway engine

5. Experiment of spring balance Students are demonstrated the working of spring balance for visible change of length / extension by applying load / weight as force Extension is directly proportional to force enables force to be measured or quantified

6. Examples of changes from rest to motion A car starts after its engine is switched on A ball is thrown by a player A ball kicked from the centre of the field A rocket is fired from a launching pad An arrow is shot from a bow A bullet is fired from the gum

7. Examples of changes from motion to rest Brakes are applied to a car A ball is caught by a player An electric fan is switched off A bullet hits the sand bag A iron ball dropped in jar filled with water

8. Vocabulary for puzzles: Make a word-search puzzle Experience Tend Cause State Speed Striking Net Resultant Bouncing