One of the most basic things students do in a physics lab is to collect data and use that to build a model. Most of these models come in the form of a mathematical function. But here is the problem.

In a distance-time graph, the gradient of the line is equal to the speed of the object. The greater the gradient (and the steeper the line) the faster the object is moving.

This video explains how the direction and gradient of a line on a velocity-time graph can tell us whether an object is accelerating, moving at a constant velocity or decelerating. Velocity time graphs ...