Speed and Velocity |
For example: Jenny ran 100m at the speed of 30km/h, how long did it take her to finish the race, please leave your answer in seconds. Notice that there are different units of measurement all over the place here, first we have to convert that km/h into m/s before we even begin to solve the problem:  Now that our units of measurement are the same (meters and seconds), we can now calculate the number of seconds it took Jenny to run 100m as follows:  VelocityIf we think about Jenny's speed from start to finish, it'll vary hugely throughout the journey. At the beginning she will struggle to pick up the speed, once she is set she will pick up and toward the crossing line she is likely to slow down so she can stop right after crossing the line. Thus it is easier to calculate her average speed for the whole journey. What if she turned a corner and changed direction and then moved faster or slower after turning a corner? That is when the concept of velocity comes into play. Velocity is defined as speed in a particular direction. In other words we could say that Jenny ran at the speed of 8.33m/s northwards, if Jenny ran around a corner without changing her speed, the average speed would not change, but the velocity will change because she will no longer be running northwards. |
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In physics, understanding physics distance and time is important and knowing two of the three, you can actually calculate the value of the other. For example if we knew the distance and average speed, it would be easy to calculate the amount of time it takes an obj