When can a body move with zero acceleration? Represent the condition with a velocity time graph.

To understand when a body can move with zero acceleration, we first need to clarify what acceleration means. Acceleration is the rate of change of velocity over time. Therefore, if a body has zero acceleration, it means that its velocity is not changing. This can happen in two scenarios: when the body is at rest or when it is moving at a constant velocity. Let’s break this down further.

Conditions for Zero Acceleration

There are primarily two conditions under which a body can have zero acceleration:

• At Rest: If an object is stationary, its velocity is zero, and since it is not changing its position over time, its acceleration is also zero.
• Constant Velocity: If an object is moving at a constant speed in a straight line, its velocity remains the same, resulting in zero acceleration. For example, a car cruising on a highway at a steady speed of 60 km/h has zero acceleration as long as it maintains that speed.

Velocity-Time Graph Representation

A velocity-time graph is a useful tool to visualize these concepts. On such a graph, the x-axis represents time, while the y-axis represents velocity. Here’s how to represent the two conditions:

1. Object at Rest

For an object at rest, the graph would be a horizontal line along the time axis (y=0). This indicates that the velocity is zero at all times.

2. Object Moving at Constant Velocity

For an object moving at a constant velocity, the graph would be a horizontal line above the time axis. For instance, if the object moves at a constant velocity of 5 m/s, the line would be parallel to the time axis at the 5 m/s mark. This indicates that the velocity does not change over time, hence zero acceleration.

Graphical Illustration

Imagine a graph where:

• The horizontal line at y=0 represents an object at rest.
• The horizontal line at y=5 represents an object moving at a constant velocity of 5 m/s.

In both cases, the slope of the line is zero, indicating that there is no change in velocity over time, which confirms that the acceleration is indeed zero.

Real-World Examples

Consider a train that comes to a complete stop at a station. While it is stationary, it has zero acceleration. Now, think of a bicycle moving steadily on a flat road without speeding up or slowing down. In both scenarios, the acceleration remains zero, illustrating the concept effectively.

In summary, a body can move with zero acceleration when it is either at rest or moving at a constant velocity. The velocity-time graph serves as a clear visual representation of these conditions, helping to reinforce the understanding of motion in physics.