ENGR101 Lecture 1 units and quantities Post Lecture

Learning Objectives

  • Understand the basic quantities and units in Engineering.

  • Apply understanding of these quantities to calculations.

  • Grasp the engineering science behind these quantities.

Key Content Areas

Quantities and Orders of Magnitude

  • Fundamental to handle various scales in engineering.

Force

  • Defined as an influence that causes motion or stress; measured in Newtons (N).

  • Force in Mechanics: ( F_{m} = m imes a ).

  • Force in Electrical Engineering: ( F_{e} = Q imes E ).

Work, Energy, and Power

  • Work: Force causing displacement, measured in Joules (J).

  • Energy: Capacity to do work, also measured in Joules.

  • Power: Rate of doing work, measured in Watts (W or J/s).

Engineering Disciplines

  • Mechanics: Involves concepts of forces, energy, and work.

  • Chemical Engineering: Focuses on heat transfer and enthalpy.

  • Electrical Engineering: Involves electric fields, voltage, and energy transfer.

Fundamental Quantities & SI Units

  • Length: meter (m)

  • Mass: kilogram (kg)

  • Time: second (s)

  • Electric current: Ampere (A)

  • Temperature: Kelvin (K)

  • Amount of substance: mole (mol)

  • Luminous intensity: candela (cd)

Orders of Magnitude

  • Significant in expressing values across scales; e.g.:

    • Femto (f, 10^-15)

    • Pico (p, 10^-12)

    • Nano (n, 10^-9)

    • Micro (μ, 10^-6)

    • Milli (m, 10^-3)

    • Kilo (k, 10^3)

    • Mega (M, 10^6)

    • Giga (G, 10^9)

Important Calculations

  • Example of Force Calculation:

    • Acceleration due to Force: ( a = \frac{F}{m} )

    • Electric Field Size: ( E = \frac{F}{Q} )

Work, Energy & Power Formulas

  • Work Done: ( W = F \cdot x )

  • Potential Energy: ( E_{p} = mgh )

  • Kinetic Energy: ( E_{k} = \frac{1}{2}mv^2 )

  • Chemical Engineering focuses on heat and enthalpy changes.

Summary

  • Key points about magnitudes, force, work, energy, and power:

    • Units of Force: Newton (N)

    • Units of Work and Energy: Joules (J)

    • Power Units: Watts (W)

Further Reading

  • Refer to Hambley for Electrical Engineering concepts and Structural Analysis for theories on force and deformation.