Velocity-time graphs show how the velocity (or speed) of a moving object changes with time. These graphs also show if the object is moving at a constant speed or accelerating, decelerating, or still.

Real life situations such as travelling over time and across distance can be drawn on a graph. Exact distances and times are plotted on the graph. These are shown as co-ordinates. These points are ...

Problem: How many colors are needed so that if each point in the plane is assigned one of the colors, no two points which are exactly distance 1 apart will be assigned the same color? This problem has ...