Distance and Displacement MCQs Quiz | Class 9

Class IX Science (Code 086) Quiz from Unit III: Motion, Force and Work. This quiz covers Distance and Displacement, focusing on Definitions, differences, and examples. Attempt the 10 multiple-choice questions below, submit to check your score, and download the answer PDF for revision.

Understanding Distance and Displacement

In the study of Motion (Class 9 Science), understanding the difference between distance and displacement is fundamental. These two quantities may seem similar but define movement in very different ways.

1. Distance

Definition: Distance is the total path length covered by an object during a given time, irrespective of direction.

  • It is a scalar quantity (has only magnitude, no direction).
  • It can never be zero or negative for a moving body.
  • The SI unit is the meter (m).
  • Example: If you walk 5 meters East and then 5 meters West, the distance traveled is 10 meters.

2. Displacement

Definition: Displacement is the shortest straight-line distance between the initial position and the final position of an object, along with direction.

  • It is a vector quantity (has both magnitude and direction).
  • It can be positive, negative, or zero.
  • The SI unit is the meter (m).
  • Example: If you walk 5 meters East and then 5 meters West (returning to the start), your displacement is 0 meters.

Key Differences

Feature Distance Displacement
Type Scalar Vector
Value Always Positive Positive, Negative, or Zero
Path Depends on path taken Independent of path (Initial to Final)
Magnitude Greater than or equal to displacement Less than or equal to distance

Quick Revision Notes

  • Odometer: The device in vehicles that measures the distance traveled.
  • Circular Motion: If a body completes one full circle, its distance is the circumference (2 pi r), but its displacement is zero because the start and end points are the same.
  • Straight Line Motion: Only when an object moves in a straight line without changing direction, the magnitude of distance equals the magnitude of displacement.

Extra Practice Questions

  1. A particle moves 3 m North, then 4 m East. What is the distance? (Answer: 7 m)
  2. A particle moves 3 m North, then 4 m East. What is the displacement? (Answer: 5 m, calculated by Pythagoras theorem)
  3. Can displacement be greater than distance? (Answer: No, never)
  4. What is the displacement of a satellite after one orbit? (Answer: Zero)
  5. If a car travels 100 km and returns to the garage, what does the odometer show? (Answer: 200 km – added distance)