Mechanical properties of solids & fluids

Question 1

Elongation due to self weight

Answer 1

ΔL = MgL/2AY

Question 2

For a suspended body, tension is max at

Answer 2

top

Question 3

Modulus of rigidity/shear mod

Answer 3

G = Fl/Ax

Question 4

For most metals G =

Answer 4

Y/3

Question 5

Bulk modulus

Answer 5

B = -dPV/dV

Question 6

Compressibility C =

Answer 6

1/B

Question 7

Poisson’s ratio σ =

Answer 7

(-ΔD/D)/(ΔL/L)

Question 8

if σ = 0.5, ΔV =

Answer 8

0

Question 9

Comparison b/w a spring and an elastic rod

Answer 9

x = FL/AY

Question 10

Elastic PE

Answer 10

U = 1/2YA/L ΔL^2

Question 11

Elastic energy density

Answer 11

u = 1/2 x stress x strain

Question 12

Breaking stress σb =

Answer 12

F(b)/A

Question 13

Breaking stress depends only on

Answer 13

material

Question 14

Sag in a doubly supported beam δ =

Answer 14

WL^3/4bd^3Y

Question 15

When liq is acc, ΔP

Answer 15

ρ(g+a)h

Question 16

When liq is decc, ΔP =

Answer 16

ρ(g-a)h

Question 17

When liq is in free fall ΔP =

Answer 17

0

Question 18

For hydraulic lift F2 =

Answer 18

F2 = A2F1/A1

Question 19

Buoyancy/Buoyant force/Upthrust F =

Answer 19

(P2-P1)A

Question 20

Archimedes principle

Answer 20

Buoyant force = weight of liq displaced by obj
B = ρ(fluid)V(immersed)g

Question 21

Under completre immersion, Loss of weight exp by obj B =

Answer 21

ρ(L) mg/ρ(o)

Question 22

App. weight Wa =

Answer 22

W - B

Question 23

If ρ > σ, obj

Answer 23

sinks

Question 24

Flotation

Answer 24

When an obj floats, it exp a buoyant force which is equla to obj weight
ρ<σ

Question 25

V(immersed)/V =

Answer 25

ρ(obj)/σ(fluid)

Question 26

ρ of ice

Answer 26

0.9 g/cm^3

Question 27

ρ of water =

Answer 27

1g/cm^3

Question 28

In streamline flow,what doesn’t change with time?

Answer 28

vel

Question 29

Discharge/flow rate

Answer 29

Vol flowing through a cross section per unit time
Q = dV/dt

Question 30

Eqn of continuity

Answer 30

Vol discharge entering = vol. discharge leaving

Question 31

For branched tube, discharge Q =

Answer 31

Q1 + Q2

Question 32

Bernoulli’s theorem

Answer 32

For a confined incompressible liq, sum of press energy/Vol, PE & KE per unit vol is const
P + 1/2ρV^2 + ρgh = const

Question 33

Bernoulli’s therom is based on conservation of

Answer 33

energy

Question 34

In horizontal tube

Answer 34

P1 + 1/2ρV1^2 = P2 + 1/2ρV2^2

Question 35

Velocity of efflux Vo =

Answer 35

√2gh

Question 36

range of efflux R =

Answer 36

2√h(H-h)

Question 37

For efflux, R is max when

Answer 37

h = H/2

Question 38

Closed tank Vo =

Answer 38

√2(P-Po)/ρ +2gh

Question 39

For venturimeter, V1 =

Answer 39

√2gh/[(A1^2/A2^2) - 1]

Question 40

Viscosity cause due to

Answer 40

intermolecular attract of liq & collision in gas molecules

Question 41

For liq, viscosity increases when temp

Answer 41

decrease

Question 42

Stoke’s law

Answer 42

Fv = 6πηrV

Question 43

Terminal vel V(T) =

Answer 43

2/9(ρ-σ)/η gr^2

Question 44

Excess press

Answer 44

Pconvex < Pconcave

Question 45

For spherical surface,

Answer 45

Pconc - Pconv = 2T/R

Question 46

For drop, ΔP =

Answer 46

2T/R

Question 47

For bubble, ΔP =

Answer 47

4T/R

Question 48

Capillary rise h =

Answer 48

2Tcosθ/rρg