Distance–Time Graphs MCQs Quiz | Class 9

Test your understanding of Class IX Science (Code 086), Unit III: Motion, Force and Work. This quiz covers Uniform motion graphs and the meaning of slope in distance-time graphs. Click Submit to see your score and download the answer key PDF.

Overview of Distance-Time Graphs

A distance-time graph is a powerful tool in physics used to visualize the motion of an object. By plotting distance on the vertical axis (y-axis) and time on the horizontal axis (x-axis), we can determine how an object’s position changes over a period. This graph helps us understand the speed and nature of motion without complex calculations.

Key Concepts

  • Slope Represents Speed: The most critical feature of a distance-time graph is its slope (or gradient). The slope is calculated as the change in distance divided by the change in time. Since Speed = Distance / Time, the slope of the graph directly gives the speed of the object.
  • Steeper Slope: A steeper line indicates a greater slope, which means the object is moving at a higher speed.
  • Flat Line: A horizontal line indicates that the distance is not changing as time passes. This means the speed is zero, and the object is at rest.

Types of Motion on Graphs

Shape of Graph Type of Motion Interpretation
Straight inclined line Uniform Motion Constant speed throughout the journey.
Curved line Non-Uniform Motion Speed is changing (accelerated motion).
Horizontal line Stationary The object is not moving.

Quick Revision Notes

Remember that a distance-time graph can never be a vertical line parallel to the distance axis. This would imply that an object is covering distance without any time passing, which means infinite speed and is physically impossible. Also, for uniform motion, the distance is directly proportional to time.

Extra Practice Questions

  1. If a car travels equal distances in equal intervals of time, what is the shape of its distance-time graph?
  2. What is the speed of a body whose distance-time graph is a horizontal line parallel to the time axis?
  3. Can the distance-time graph of a moving body go downwards (negative slope) if distance is total path length?
  4. How do you calculate the speed from a specific section of a distance-time graph?
  5. Which physical quantity is represented by the area under a distance-time graph? (Trick question: none).