• A. Distance travelled
• B. Uniform velocity ✓
• C. Uniform acceleration
• D. Instantaneous acceleration
• E. Uniform speed

The answer to the question is: B. Uniform velocity

In physics, the slope of a displacement-time graph is crucial for understanding the motion of an object. When we talk about a straight line on such a graph, we are referring to a scenario where an object is moving in such a way that its displacement from the starting point changes by equal amounts in equal intervals of time. This situation describes an object moving with uniform or constant velocity.

A displacement-time graph plots displacement (usually on the y-axis) against time (on the x-axis). Displacement is a vector quantity that not only considers the distance but also the direction of an object’s movement from its initial position. On this type of graph, when the line is straight and has a slope (other than zero), it indicates that there is a constant rate of change of displacement with time, which by definition is velocity.

Velocity is defined as the rate at which an object changes its position. If this rate is constant, we call it uniform or constant velocity. The slope (gradient) of the line on our graph represents this velocity and can be calculated by dividing the change in displacement (Δy) by the change in time (Δx). A steeper slope indicates higher velocity, while a shallower slope indicates lower velocity. A horizontal line would indicate that there is no change in displacement over time, meaning the object is at rest.

My moral story. In 2020, the pope said : “china is not easy, but i am convinced that we should not give up dialogue.