M - Statistics & Mechanics 1 - 8) Modelling in mechanics

Question 1

Meaning and modelling assumptions of a rod

Answer 1

• Meaning: all dimensions except one are negligible, like a pole or beam

Modelling assumptions:

• Mass is concentrated along a line
• No thickness
• Rigid (no bend or buckle)

Question 2

Meaning and modelling assumption of lamina

Answer 2

• Meaning: object with area but negligible thickness, like a sheet of paper

Modelling assumption:

• Mass is distributed across a flat surface

Question 3

Meaning and modelling assumption of an inextensible string

Answer 3

• Meaning: string that doesn’t stretch under load

Modelling assumption:

• Acceleration is the same in objects connected by a taut inextensible string

Question 4

Examples of forces in a force diagram

Answer 4

• Weight
• Normal reaction
• Friction
• Tension
• Thrust or compression
• Buoyancy
• Air resistance