Week 8 Elasticity, Bulk Modulus and Liquids

Question 1

define elasticity

Answer 1

ability of a body to undergo permanent non-reversible deformation in response to an external force

Question 2

what is the youngs modulus eqn

Answer 2

γ = (F/A) / (x/L) = tensile stress / tensile strain

Question 3

when is youngs modulus useful

Answer 3

when analysing transverse extension of a solid

Question 4

what is the shear modulus eqn

Answer 4

S = (F/A) / (l-l0 / h) = Shear stress / shear strain

Question 5

when is shear modulus useful

Answer 5

when analysing longitudinal extension of a solid

Question 6

what is the bulk modulus eqn

Answer 6

B = -ΔP / (ΔV/V0)

Question 7

what is the compressibility

Answer 7

k = -1/B

Question 8

when is bulk modulus useful

Answer 8

when considering the volumetric compression/expansion of a solid

Question 9

what is the archimedes principle

Answer 9

when a solid object is submerged in a liquid in a container the height of the liquid in the container increases

Question 10

what is true of submerged volumes

Answer 10

volume of the solid that is submerged = volume of liquid displaced

Question 11

what is the buoyant force eqn

Answer 11

Fb = ρ(liq)V(dis)g

Question 12

how do we determine in an object sinks or floats

Answer 12

sinks when mg > Fb

floats when mg < Fb

Question 13

what is the fluid pressure eqn

Answer 13

ΔP = Δhρ(liq)g

Question 14

briefly describe the torricelli experiment setup

Answer 14

have a container with a long thin tube at the top of the lid with a vacuum and fill container with a liquid

Question 15

what is true of mass flow rate and its associated eqn

Answer 15

mass flow rate is constant

Δm/Δt = (ρ1A1l1)/Δt = (ρ2A2l2)/Δt

Question 16

what is the Bernoulli eqn

Answer 16

P1 + 1/2ρv1^2 + ρh1g = P2 + 1/2ρv2^2 + ρh2g