How to determine the speed from a distance-time graph?

The speed from a distance-time graph is determined by calculating the gradient of the line.

In a distance-time graph, the speed of an object is represented by the slope or gradient of the line. The steeper the line, the faster the speed. If the line is horizontal, it means the object is stationary. If the line is straight but sloping, it means the object is moving at a constant speed. If the line is curved, it means the object is accelerating or decelerating.

To calculate the speed, you need to find the gradient of the line. This is done by dividing the change in distance (vertical axis) by the change in time (horizontal axis). In other words, speed = distance/time. For a straight line, you can pick any two points on the line to calculate the gradient. For a curved line, you would need to draw a tangent to the curve at the point where you want to find the speed, and then calculate the gradient of this tangent.

Remember, the units of speed will be determined by the units of distance and time used on the graph. For example, if distance is in metres and time is in seconds, the speed will be in metres per second (m/s).

In summary, understanding the gradient of a distance-time graph is key to determining the speed of an object. It's a simple but powerful tool in physics that allows us to visualise and calculate how speed changes over time.