Materials

Question 1

Practical to find density of object

Answer 1

1. Find mass using balance

2. Find volume from eureka can or measure with ruler

Question 2

Equation for dencity

Answer 2

Decity=volume/area

In either kgm‐³ or gcm‐³

Question 3

Calculating density of alloys

Answer 3

Find and add their masses, add their volumes and THEN calculate dencity

Question 4

Hooke’s Law

Answer 4

F=ke
Below the limit if proportionality
Nm‐¹

Question 5

Spring constant in parallel vs series

Answer 5

Single: ks
Series:ks×n‐¹
Parallel: ks×n

Question 6

Work done in a spring

Answer 6

(Have to account for work done against spring)

E=½Fe
E=½F²e‐¹
E=½ke²

Question 7

Plastic behaviour

Answer 7

Beyond limit of elasticity

Permanently deformed

Question 8

Elastic behaviour

Answer 8

Below limit of elasticity

Can return to original form

Question 9

Ductile material

Answer 9

Can be put under high tensile stress without fracture

Question 10

Brittle material

Answer 10

Cant be put under high stress

Fractures easily

Question 11

Strong material (tensile strength)

Answer 11

Can withstand high tensile stress with only small extention

Question 12

Calculation for tensile stress

Answer 12

F/A

A= cross sectional are perpendicular to force
PASCALS

Question 13

Calculation for tensile strain

Answer 13

extention/length

Longer the length, the more it would stretch
This gives universal value for particular material

Question 14

P (limit of proportianality)

Answer 14

Point beyond which hooks law is no longer true

Question 15

E (elastic limit)

Answer 15

Furthest point it can be steetched/deformed

While being able to return to original shape

Question 16

Y (yield stress)

Answer 16

Stress beyond which a material has plastic behaviour

Question 17

UTS (Ultimate tensile stress)

Answer 17

Max stress a material can withhold

Without fracturing

Question 18

Youngs modulus

Answer 18

Measure of the stiffness of material

Stress/strain= Fl/Ae

Question 19

Rubber material

Answer 19

Elastic but has no Hookes Law region

Loading and unloading curves are different

Question 20

Area under stress strain graph

Answer 20

Is equal to energy stored or work done per unit volume

Areea=½Fe/Al(volume)

Often referred to as STRAIN ENERGY DENSITY