Describing Motion Around Us
Class 9 · Science
4 ideas in Class 9 Science, explained in plain words, with games and quizzes to practise.
Position, Distance and Displacement
Part of: Position, Distance and Displacement
Position depends on a chosen reference point and direction. Distance adds the full path, while displacement is the directed change between start and finish.
Why it matters. These ideas help describe and compare how objects move, including changes in direction and speed.
Try it in two minutes
- Choose a reference point and identify the time interval.
- Decide whether the question asks about path, position change, or velocity change.
- Use the matching definition or graph feature to reason.
Try at home. Watch a toy move along a straight path and describe its position at two moments using a fixed starting point.
Average Speed and Average Velocity
Part of: Average Speed and Average Velocity
Average speed uses total distance over elapsed time. Average velocity uses displacement over elapsed time and includes direction.
Why it matters. These ideas help describe and compare how objects move, including changes in direction and speed.
Try it in two minutes
- Choose a reference point and identify the time interval.
- Decide whether the question asks about path, position change, or velocity change.
- Use the matching definition or graph feature to reason.
Try at home. Watch a toy move along a straight path and describe its position at two moments using a fixed starting point.
Acceleration and Motion Graphs
Part of: Acceleration and Motion Graphs
Acceleration is change in velocity per time. Position-time slope represents velocity, while velocity-time slope represents acceleration and area gives displacement.
Why it matters. These ideas help describe and compare how objects move, including changes in direction and speed.
Try it in two minutes
- Choose a reference point and identify the time interval.
- Decide whether the question asks about path, position change, or velocity change.
- Use the matching definition or graph feature to reason.
Try at home. Watch a toy move along a straight path and describe its position at two moments using a fixed starting point.
Constant Acceleration and Circular Motion
Part of: Constant Acceleration and Circular Motion
For constant acceleration in a straight line, kinematic equations relate displacement, time, and initial and final velocities. In uniform circular motion, speed stays constant but velocity direction changes, so acceleration is present.
Why it matters. These ideas help describe and compare how objects move, including changes in direction and speed.
Try it in two minutes
- Choose a reference point and identify the time interval.
- Decide whether the question asks about path, position change, or velocity change.
- Use the matching definition or graph feature to reason.
Try at home. Watch a toy move along a straight path and describe its position at two moments using a fixed starting point.
What your child will practise
- Acceleration and Motion Graphs: Candy Quick Fire (Quick Fire)
- Average Speed and Average Velocity: Desert Quick Fire (Quick Fire)
- Average Speed and Average Velocity: Lab Explorer Sort (Sort It Out)
- Constant Acceleration and Circular Motion: Candy Puzzle (Clue Puzzle)
- Position, Distance and Displacement: Mission Control Quest (Collect the Answer)
- Quiz: Acceleration and Motion Graphs (8 questions)
- Quiz: Average Speed and Average Velocity (8 questions)
- Quiz: Constant Acceleration and Circular Motion (8 questions)
- Quiz: Position, Distance and Displacement (8 questions)