CBSE Class 11 Physics Mechanical Properties Of Fluids Notes

CBSE Class 11 Physics - Mechanical Properties of Fluids Notes. Learning the important concepts is very important for every student to get better marks in examinations. The concepts should be clear which will help in faster learning. The attached concepts made as per NCERT and CBSE pattern will help the student to understand the chapter and score better marks in the examinations.

Class XI

Chapter 10: Mechanical Properties of Fluids

Key Learning:

1. Fluid has a property that is flow. The fluid does not have any resistance to change of its shape. The shape of a fluid governed by the shape of its container.

2. A liquid is incompressible and has a free surface of its own. A gas is compressible and it expands to occupy all the space available to it. 

3. Liquids and gases together are known as fluids.

4. Pressure at a point is force upon area, and it is a scalar quantity. Unit of pressure is pascal. Its SI unit is N m^-2

5. Average pressure P_av is defined as the ratio of the force to area  P_av=F/A.
6. Pascal is the unit of the pressure. It is the same as N m-2. Other common units of pressure are
1 atm = 1.01 x 105 Pa
1 bar = 105 Pa
1 torr = 133 Pa = 0.133 kPa
1 mm of Hg = 1 torr = 133 Pa

7. Pressure is defined as normal force per unit area.

P=dF/dA

8. The pressure difference between two points in a static fluid of uniform density r is proportional to the depth h.

7. Pascal’s law states that a change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid.

9. Gauge pressure measures the excess pressure above the atmospheric pressure.

10. Flow of a fluid whose density is independent of both position and time is said to be incompressible.

11. If the frictional forces in a moving fluid are negligible, the flow is called non viscous.

12. If a fluid element has a nonzero angular velocity at every point, the flow is said to non-rotational.

13.Orderly flow of a fluid is called streamlined or steady flow.

14. In streamlined flow, every liquid element crossing a point has the same velocity.

15. Disorderly flow of fluid is called turbulent Flow.

16. A streamline is defined as a curve such that the tangent to any point on the curve gives the direction of fluid flow at that point.

17. Like in a steady or streamline flow, no two streamlines ever cross each other.

18. The greater is the spacing between streamlines in a region, the smaller is the fluid velocity there.

19. A bundle of streamlines forming a tubular region is called a tube of flow.

20. When the flow is incompressible, non-viscous, steady and nonrotational, it is called ideal fluid flow.

21. Equation of continuity says that the product of area of cross section and velocity remains constant through out the flow.

22. In case of varying density or compressible liquids, the equation of continuity modifies to product of the density, area of cross section and velocity of the flow remaining constant as opposed to Av =constant.

23. If the fluid velocity is less than a certain limiting value called critical velocity, the flow is steady or streamlined; as its speed exceeds the critical velocity it becomes turbulent.

24. Equation of continuity tells us that fluid speed is greater in narrow regions as compared to wider regions.

25. If the speed of a fluid element increases as it flows, the pressure of the fluid must decrease and vice versa – This is one implication of Bernoulli’s Principle.

26. Bernoulli was the first one to relate this pressure difference to velocity changes.

27. Bernoulli also explained the relation between the height of a fluid and changes in pressure and speed of fluid.

28. Along a streamline, the sum of the pressure, the kinetic energy per unit volume and the potential energy per unit

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