Elasticity

Question 1

What is stress in fomulaic form ?

Answer 1

Stress = Internal force / Cross sectional Area = F/A

Question 2

What is strain in formulaic form?

Answer 2

Strain= increase in length / Initial Length = l/L

Question 3

According to Hooke’s law, what is modulus of elasticity E in conceptual form?

Answer 3

Modulus of Elasticity E = Stress / Strain

Question 4

What is the fomulaic form of Young’s Modulus Y?

Answer 4

Youngs Modulus Y= F/A / l/L = FL /Al

Question 5

What is the bulk modulus of elasticity in formulaic form?

Answer 5

Bulk modulus of elasticity B= -P/ v/V = -PV/v

Question 6

What is the formulaic form of Compressibility ?

Answer 6

Compressibility β= 1/B= -v/PV

Question 7

What is the modulus of rigidity given by in formulaic form?

Answer 7

Modulus of rigidity η = Shearing Stress/ Shearing Strain = F/A / ∅ = F/A∅

Question 8

What is the potential energy in a stretched wire given in conceptual form?

Answer 8

Potential Energy of a stretched wire given by:

U= 1/2 Stress x Strain= 1/2 Young’s Modulus x (strain)²= 1/2 Yσ² = 1/2 YA/L l²

Question 9

What is the work done by a force F when wire is pulled down by a small distance Δx?

Answer 9

The work done by a force F when wire is pulled down by a small distance Δx is :
W = F x Δx = (T x 2l) x Δx = T x ΔA

Question 10

What is surface tention in formulaic form ?

Answer 10

Surface tention is given by:

T= W/ ΔA

Question 11

What is the formulaic representation of the excess of pressure inside a liquid drop/ air bubble ?

Answer 11

The excess of pressure inside a liquid drop/ air bubble is given by:
p = 2T / R

Question 12

What is the formulaic representation of the excess of pressure inside a soap bubble ?

Answer 12

The excess of pressure inside a soap bubble is given by:

p = 4T / R

Question 13

What is the formula of rise of a liquid in a capillary tube?

Answer 13

The rise of a liquid in a capillary tube is given by:

h = 2 T cos ∅/ r ρ g