What does a horizontal line on a position-time graph indicate about the object?

a The object has a position of zero
b The object remains still
c The object is accelerating
d the object has a constant, nonzero velocity

b The object remains still

The correct answer is b) The object remains still. A horizontal line on a position-time graph indicates that the object has a constant position over time, meaning it is not changing its location and is therefore remaining still.

A horizontal line on a position-time graph indicates that the object has a constant, nonzero velocity. This means that the object is moving at a constant speed in a specific direction. In order to identify this on a position-time graph, you can use the following steps:

1. Understand the axes: The horizontal axis represents time, while the vertical axis represents the position or displacement of the object.

2. Analyze the slope: The slope of a position-time graph represents the object's velocity. A horizontal line has a slope of zero since it is perfectly flat. A zero slope indicates that there is no change in position over time. Therefore, the object has a constant velocity.

3. Determine the velocity: When an object has a horizontal line on a position-time graph, it means that the object is moving with a constant velocity. The line indicates that the object is neither speeding up nor slowing down, but rather maintaining a steady speed.

Based on the above explanation, the correct answer is option d: The object has a constant, nonzero velocity.