Speed vs Velocity

Back to Physics Grade 9/10


This is a simple physics tutorial aimed at high school students in grades 9 and 10 (GCSE, HSC) exploring what the difference is between speed and velocity.

What's the same between speed and velocity?

Both speed and velocity can tell us how fast an object or person is travelling.

What's the difference between speed and velocity?

In simple terms, speed is a scalar measurement so it only gives us magnitude (how fast the object is travelling). Velocity is a vector measurement and thus tells us both how fast something is travelling AND the direction it's travelling in. This is because although they share the same denominator (time), their numerator is different (as below - hover over the image).

You can learn more about distance and displacement here.

Constant speed and changing velocity

This key difference means that it is possible for an object to travel with a constant speed, but with a changing velocity. How? Have a think about an object travelling at a constant speed in a circle; for example, a car racing around a circular race track at a constant speed; say 10m/s.

The object can travel around the circular track at a constant speed, but because the direction this object is moving in changes every second, so too does its velocity.

Exercise Worksheet

Below is the follow on worksheet for this video. It has three sample calculations so that you can see what you need to do to calculate the average speed of an object and report the value in any three of the suggested units. It also has four exercises that you can work through in your own time, with answers given in meters per second, kilometers per hour and miles per hour. To download the worksheet, visit Slideshare here:

Make notes

Want to make notes as you follow along? Visit Slideshare to download the below document: