How to Find Velocity

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How to Find Velocity

Velocity is the speed with a direction. It is also described as the change in position over the change in time. Velocity is the rate at which displacement changes with time. Here is how to Calculate Velocity

How to Find the Simple Velocity

  1. Write down the Velocity Formula

    \mathbf{Velocity = \frac{Displacement}{Time}} in a direction.

  2. Plug the values into the formula.

    Example: John walks from his home to school in 6 minutes and 40 seconds, what is his velocity?

    Displacement = 200 m And Time = 6 minutes and 40 seconds = 400 s

    Velocity = \mathbf{\frac{200\ m}{400\ s}}  North-West = 0.50 m/s North-west

How to Find Average Velocity

  1. Write the formula for Average Velocity.

    \\\mathbf{\\Average Velocity = V_{av} = \frac{x_{f}-x_{i}}{t_{f}-t_{i}} = \frac{\bigtriangleup x}{\bigtriangleup t}} \\ \\\boldsymbol{\\x_{f} = final\ position\ x_{i} = initial\ position} \\ \\\mathbf{\\t_{f} = final\ time\ t_{i} = initial\ time}

  2. Find the distance between the start and end points. 

  3. Subtract the start time from the end time to find out the change in time.

  4. To find out the average velocity, divide the total displacement by the total time. 

Example: A car traveling due east starts at position x = 0 meters. After 8 seconds, the car is at position x = 72 meters. What was the car’s displacement?

\\\mathbf{\\Average Velocity = V_{av} = \frac{x_{f}-x_{i}}{t_{f}-t_{i}} = \frac{72m - 0m}{8s - 0s} = \frac{72m}{8s} = 9 \frac{m}{s}\ East}

How to Find Average Velocity when Acceleration is Constant

  1. Write the formula for Average Velocity if acceleration is constant.