What does a velocity-time graph represent?

A velocity-time graph represents how an object's velocity changes over time.

In a velocity-time graph, the y-axis shows the velocity of the object, while the x-axis represents time. This type of graph is incredibly useful for understanding the motion of an object, as it provides a visual representation of how the speed and direction of the object change over a period.

One of the key features of a velocity-time graph is that the slope (or gradient) of the line indicates the object's acceleration. If the line is horizontal, it means the object is moving at a constant velocity. A sloping line upwards indicates positive acceleration (speeding up), while a sloping line downwards indicates negative acceleration (slowing down). The steeper the slope, the greater the acceleration.

Another important aspect is that the area under the line on a velocity-time graph represents the displacement of the object. Displacement is the overall change in position of the object. For example, if you have a straight line above the time axis, the area between this line and the time axis gives you the distance travelled in that time period. If the line is below the time axis, it indicates the object is moving in the opposite direction.

Velocity-time graphs can also show more complex motions. For instance, a curved line indicates changing acceleration, meaning the rate of acceleration itself is not constant. This can happen in real-world scenarios like a car speeding up and then slowing down in a non-uniform manner.

Understanding how to read and interpret velocity-time graphs is a fundamental skill in GCSE Physics, as it helps you analyse various types of motion and solve related problems effectively.