You should be able to understand the concept of
speed
constant speed
average speed
Read and try to understand Textbook 1B explanations and worked examples: pg 64 to 65.
Speed = Distance / Time
Read and try to understand Textbook 1B explanations and worked examples: pg 65 to 68.
Average Speed = Total Distance / Total Time
If the speed of an object does not change throughout its journey, the object is said to be travelling at a constant speed.