SI Units and Measurement Basics

Measurements

• International System of Units (SI)
  • Developed to provide a consistent and coherent system of units for physical quantities
  • Based on seven base units:
    • Meter (m) for length
    • Kilogram (kg) for mass
    • Second (s) for time
    • Ampere (A) for electric current
    • Kelvin (K) for thermodynamic temperature
    • Mole (mol) for amount of substance
    • Candela (cd) for luminous intensity
• Derived Units
  • Formed by combining base units
  • Examples:
    • Velocity: m/s
    • Acceleration: m/s^2
    • Force: N (Newton) = kg·m/s^2
    • Energy: J (Joule) = N·m
• Uncertainty and Significant Figures
  • Measurements always have some degree of uncertainty
  • Significant figures indicate the precision of a measurement
  • Rules for significant figures:
    • Non-zero digits and zeros between non-zero digits are significant
    • Leading zeros and trailing zeros are not significant

Motion

• Describing Motion
  • Displacement: Change in position, Δx = x_f - x_i
  • Distance: Total length of path traveled
  • Speed: Rate of distance traveled, v = Δx / Δt
  • Velocity: Rate of displacement, v = Δx / Δt
• Types of Motion
  • Rectilinear Motion: Motion along a straight line
  • Circular Motion: Motion along a circular path
  • Rotational Motion: Motion around a fixed axis
• Equations of Motion
  • Uniform Acceleration: a = constant
  • Equations:
    • v = v0 + at
    • x = x0 + v0t + (1/2)at^2
    • v^2 = v0^2 + 2a(x - x0)
• Graphical Analysis
  • Position-Time Graphs: Slope = velocity
  • Velocity-Time Graphs: Slope = acceleration
  • Acceleration-Time Graphs: Slope = jerk (rate of change of acceleration)

International System of Units (SI)

• Developed to provide a consistent and coherent system of units for physical quantities
• Based on seven base units:
  • Meter (m) for length
  • Kilogram (kg) for mass
  • Second (s) for time
  • Ampere (A) for electric current
  • Kelvin (K) for thermodynamic temperature
  • Mole (mol) for amount of substance
  • Candela (cd) for luminous intensity

Derived Units

• Formed by combining base units
• Examples:
  • Velocity: m/s
  • Acceleration: m/s^2
  • Force: N (Newton) = kg·m/s^2
  • Energy: J (Joule) = N·m

Uncertainty and Significant Figures

• Measurements always have some degree of uncertainty
• Significant figures indicate the precision of a measurement
• Rules for significant figures:
  • Non-zero digits and zeros between non-zero digits are significant
  • Leading zeros and trailing zeros are not significant

Motion

Describing Motion

• Displacement: Change in position, Δx = x_f - x_i
• Distance: Total length of path traveled
• Speed: Rate of distance traveled, v = Δx / Δt
• Velocity: Rate of displacement, v = Δx / Δt

Types of Motion

• Rectilinear Motion: Motion along a straight line
• Circular Motion: Motion along a circular path
• Rotational Motion: Motion around a fixed axis

Equations of Motion

• Uniform Acceleration: a = constant
• Equations:
  • v = v0 + at
  • x = x0 + v0t + (1/2)at^2
  • v^2 = v0^2 + 2a(x - x0)

Graphical Analysis

• Position-Time Graphs: Slope = velocity
• Velocity-Time Graphs: Slope = acceleration
• Acceleration-Time Graphs: Slope = jerk (rate of change of acceleration)