class 9th ppt Thrust and pressure.pptx

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1. Class -9 Chapter- Gravitation Thrust and Pressure

2. The force applied on a surface in a direction perpendicular to the surface of an object. SI unit newton Thrust

3. pressure The effect of thrust per unit area is called pressure. Pressure =Thrust /Area Unit Pascal (Pa) 1 Pa = 1N/1 m 2

4. Pressure Depend On Two Factor 1. Force (thrust) - more force more pressure 2. Area - more area less pressure

5. “The same force produce less pressure if it acts on a large area but can produce less pressure if acts on a small area.”

6. Every day observation 1.school bag have wide straps so the weight of bag may fall over a large area of the shoulder of the student producing less pressure on shoulder .

7. Sharp knife cut better than a blunt knife so the force of our hand fall over a very small area of object produce large pressure.

8. The tractor have broad tyres so there is less pressure on ground and do not sinking to comparatively soft field

9. It is easier to walk on soft sand if we have flat shoe rather than shoes with sharp heels.

10. The foundation of building and dams are laid on larger area to produce less pressure

11. >The wooden or concrete sleepers are kept below the railway line. >A wide belt is provided over the wheels of an army tank

12. Home work /assessment. 1. Define thrust .What is its unit ? 2.What is relation between pressure , force and area ? 3.Name the quantity Whose one of the unit is pascal (Pa)? 4.Why does a sharp knife cut objects more effectively than a blunt knife ? 5.Why the tip of sewing needle is sharp? 6.Why snow shoes stop you from sinking into snow ?

13. Thank - you