Velocity–Time Graphs MCQs Quiz | Class 9
Class IX Science (Code 086) Unit III: Motion, Force and Work. This quiz focuses on Velocity–Time Graphs, covering uniform motion, uniformly accelerated motion, and the interpretation of slope and area under the graph. Submit your answers to view results and download the PDF solution.
Understanding Velocity-Time Graphs
In Class IX Science, specifically Unit III: Motion, Force and Work, the velocity-time (v-t) graph is a crucial tool for analyzing motion. These graphs plot velocity on the y-axis against time on the x-axis.
Key Interpretations
- Slope (Gradient): The slope of a v-t graph represents the acceleration of the object. A steeper slope indicates higher acceleration.
- Area Under the Curve: The area enclosed between the graph line and the time axis represents the displacement (or distance magnitude) covered by the object during that time interval.
Types of Motion on V-T Graphs
We generally encounter three main scenarios in uniform acceleration problems:
- Uniform Motion (Constant Velocity): The graph is a straight line parallel to the time axis. The slope is zero, meaning acceleration is zero.
- Uniformly Accelerated Motion: The graph is a straight line inclined to the time axis. If it passes through the origin, the object started from rest.
- Non-Uniform Acceleration: The graph is a curved line, indicating that velocity is changing at a variable rate.
Quick Summary Table
| Shape of Graph | Type of Motion | Acceleration |
|---|---|---|
| Horizontal straight line | Uniform Motion | Zero |
| Straight line with positive slope | Uniform Acceleration | Constant (Positive) |
| Straight line with negative slope | Uniform Retardation | Constant (Negative) |
| Curved line | Non-Uniform Acceleration | Variable |
Practice Questions
1. If a car comes to a stop, how does the v-t graph look? (Answer: A line sloping downwards to the time axis).
2. Can a v-t graph be a vertical line? (Answer: No, because an object cannot have multiple velocities at a single instant of time).
3. What represents instantaneous acceleration? (Answer: The slope of the tangent at a specific point on a curved v-t graph).
4. Does the area under the v-t graph give speed? (Answer: No, it gives displacement or distance travelled).
5. What does a negative velocity region imply? (Answer: The object is moving in the opposite direction).
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