Mechanics Of Solid And Fluid

Question 1

Define surface tension

Answer 1

It is the tangential force acting per unit length on both side of the imaginary line

Question 2

Define Surface energy

Answer 2

The extra energy of molecules in surface layer is called as surface energy

Question 3

Explain angle of contact

Answer 3

1) Angle of contact is defined as the angle between the tangents drawn to free surface between the surface of liquid and the surface of solid, measured within the liquid.
2) When angle of contact is acute, the liquid form concave meniscus
3) when angle of contact is obtuse, the liquid form obtuse meniscus.

Question 4

State the factors affecting angle of contact

Answer 4

1) nature of liquid and solid in contact
2) impurities present
3) temperature of the liquid

Question 5

What is the effect of impurities in the liquid on angle of contact

Answer 5

1) if soluble - angle of contact increase
2) sparingly soluble- decrease
3) insoluble- decrease
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Question 6

Effect of temp in liquid on angle of contact

Answer 6

Increase in temp = increase in angle of contact

Question 7

What is capillary tube?

Answer 7

Tube having very fine bore and is open at both ends is called as capillary tube

Question 8

What is capillarity, states it’s application

Answer 8

The phenomenon of rise and fall of the liquid inside a capillary tube when dipped inside the liquid.

1) oil raise up the wick in lamp
2) cloth rag sucks water
3) blotting paper absorbs ink

Question 9

Differentiate between streamline flow and Turbulent flow

Answer 9

Streamline flow
1) the smooth flow of liquid when the velocity is smaller the critical velocity
2) velocity is constant
3) two streamline can never intersect each other, they are always parallel
4) Flow is streamline if the Reynolds number is less ghe 1000

Turbulent flow
1) the irregular and unsteady flow of the liquid ehen velocity is greater the critical velocity
2) velocity is not constant
3) Turbulent flow can intersect each other
4) the flow is turbulent, if the Reynolds number is greater then 2000

Question 10

State Bernoulli’s principal

Answer 10

The work done per unit volume by a liquid by surrounding liquid is equal to sum of kinetic energy and potential energy per unit volume that occurs during the flow