Solids and Fluids L1

Question 1

When Fnet = 0

Answer 1

Object is not accelerating

Question 2

What is stress

Answer 2

It is the internal forces exerted on imaginary internal surfaces in response to external applied forces

Question 3

What is strain?

Answer 3

Change in the shape of an object in response to stress

Question 4

States of matter

Answer 4

Solids, Liquids, Gases and Plasma

Question 5

How to solids molecules oscillate?

Answer 5

Around fixed centres

Question 6

What pattern do the amplitudes of solid molecules form?

Answer 6

The vibration of the amplitide is small and the fixed centres form a repeated spatial pattern

Question 7

What is the repeated spatial pattern solid molecules called?

Answer 7

Long range order

Question 8

What is larger in Liquids compared to solids?

Answer 8

The intermolecular distances and hence the Amplitudes of vibration

Question 9

What is short range order in liquids?

Answer 9

Regularity in structure in few immediate surrounding molecules

Question 10

What do Gas molecules have more of?

Answer 10

They have more Kinetic energy

Question 11

What is elasticity?

Answer 11

When object is subject to equal and opp. balanced forces causing it to undergo shape/size/both change but if it returns to og shape after forces are removed, it behaves elastically

Question 12

What is formula of tensile/compressive stress

Answer 12

Stress = F/A

1Pa = 1N/mˆ2

Question 13

What is tensile stress?

Answer 13

When an object is pulled from both ends

Question 14

What is tensile/compressive strain?

Answer 14

Changes in shape from L0 to L as a result of tensile/compressive stress

Strain = ∆L/L0

Question 15

How is force distributed in tensile stress?

Answer 15

Uniformly through the object

Question 16

If L > L0

Answer 16

Tensile stress is positive

Question 17

What is compressive stress?

Answer 17

Pushing equally from both ends

Question 18

If L < L0

Answer 18

Compressive stress is -ve

Question 19

What is strain?

Answer 19

Measure of relative length change

Question 20

What is Hooke’s law?

Answer 20

When stress is proportional to strain and they have both small tensile/compressive stress

Question 21

When does Young’s modulus apply?

Answer 21

When Hooke’s law is valid

Question 22

Young’s modulus formula

Answer 22

stress/strain

Can be seen as a constant if the stress + strain values are very small

Question 23

What does Young’s modulus not depend on

Answer 23

Shape or size or volume

Question 24

What does Young’s modulus depend on

Answer 24

Material of the object

two different objects of different sizes, shape or volume but of the same material will have the same young’s modulus