Velocity time graph analysis, acceleration calc

🏎 1. Velocity-Time (v-t) Graphs

🔹 Axes

  • Y-axis → Velocity (m/s)

  • X-axis → Time (s)


🔹 Key Features

Feature

Meaning

Horizontal line

Constant velocity (acceleration = 0)

Upward sloping line

Acceleration (speed increasing)

Downward sloping line

Deceleration (speed decreasing)

Area under graph

Distance travelled


🔹 Calculating Distance

  • Area under the graph = distance

  • Formulas:

    • Rectangle → width × height

    • Triangle → ½ × base × height

Example:

  • Triangle area: ½ × 4 s × 10 m/s = 20 m

  • Rectangle area: 5 s × 8 m/s = 40 m

  • Total distance = 60 m


2. Acceleration Calculations

🔹 Definition

  • Acceleration (a) = rate of change of velocity

a=change in velocitytimea = \frac{\text{change in velocity}}{\text{time}}a=timechange in velocity​


🔹 Formula

a=v−uta = \frac{v - u}{t}a=tv−u​

  • vvv = final velocity (m/s)

  • uuu = initial velocity (m/s)

  • ttt = time (s)


🔹 Example Calculation

  • Initial velocity u=2 m/su = 2\,\text{m/s}u=2m/s

  • Final velocity v=10 m/sv = 10\,\text{m/s}v=10m/s

  • Time t=4 st = 4\,\text{s}t=4s

a=10−24=84=2 m/s²a = \frac{10 - 2}{4} = \frac{8}{4} = 2\,\text{m/s²}a=410−2​=48​=2m/s²


🔹 Key Tips

  • Positive slope → positive acceleration

  • Negative slope → deceleration (negative acceleration)

  • Area under graph → distance


🔗 Big Links

  • V-t graphs → visual representation of motion

  • Acceleration = slope of the graph

  • Distance = area under the graph


Exam Tips

  • Always label velocity and time axes

  • Identify slope → acceleration

  • Use correct units → m/s² for acceleration, m for distance

  • Practice both slope and area methods