Speed and Velocity
In I/GCSE Physics, in order to properly understand the formula for Speed or Velocity we must understand the logic behind it. The formula for Speed is ‘s/t’ when s = distance and t = time.
To explain this equation we must think about it with regards to distribution. ‘s/t’ is the same as ‘s ÷ t’, so what we’re doing here is equally distributing the amount of distance we have covered onto the amount of time we have taken to cover it when in terms of seconds; five metres per second in this case.
- In the I/GCSE physics, speed is defined as the specified amount of distance travelled over a specified amount of time. e.g. The car was moving at 25m/s (m = Metres, s = Seconds). Speed is a Scalar. s/t = speed.
- Velocity is defined as Speed plus a specified direction. e.g. The car was moving North at 25m/s. Velocity is a Vector. s/t + specified direction (right, left, north, south, etc.) = Velocity.
Example:
You are driving for 5 seconds and travel a distance of 25 metres.
Diagram:
In I/GCSE physics curriculum, by explanation, we are evenly dividing the amount of distance we have covered among each second (25÷5=5). So, s/t = s÷t which is simply shorthand for the diagram above; for each second we have travelled five metres.
- Formula for Speed: s/t (Distance ÷ Time).
- [Scalar: A Scalar the term used for a ‘scalable’ value. It is only a value and cannot have anything else specified e.g. a direction.]
- Formula for Velocity: s/t + Specified Direction. e.g. right, left, north, south, etc.
- [Vector: A Vector is a Scalar with a specified direction.]
Challenge:
a) A car travels 500 metres in 20 minutes, how fast was the car going?
End of this topic!