All questions of Measurement of Length and Motion for Class 6 Exam

Understanding Rotational Motion
Rotational motion is characterized by an object rotating around an axis. Let’s analyze the options given in your question to identify which does not exemplify this type of motion.
Examples of Rotational Motion
- Movement of the Moon on Its Axis:
The Moon rotates around its own axis while also orbiting the Earth. This is a clear example of rotational motion.
- Movement of Earth on Its Axis:
The Earth spins around its axis, completing one rotation approximately every 24 hours. This is another example of rotational motion.
- Movement of Blades of a Fan:
The blades of a fan rotate around a central axis. Each blade moves in a circular path, demonstrating rotational motion effectively.
Non-Rotational Motion
- Movement of a Person on the Road:
When a person walks or runs on the road, they are moving in a linear path, not rotating around an axis. Their movement is translational, making this option the odd one out.
Conclusion
In summary, options A, B, and D involve rotational motion, while option C (movement of a person on the road) represents translational motion. This distinction is crucial for understanding different types of motion in physics.

The best unit to use to measure the tip of a pencil is the millimeter (mm).

Explanation:
- When measuring small objects like the tip of a pencil, it is important to use a unit that is appropriate for the size of the object. In this case, the millimeter is the most suitable unit because it is smaller than a centimeter (cm) and larger than a micrometer (μm).
- A millimeter is equal to one thousandth of a meter. It is a commonly used unit for measuring small distances, such as the length, width, or thickness of objects.
- The tip of a pencil is typically very small, usually less than a centimeter in length. It would be difficult to accurately measure it using larger units like meters or kilometers.
- Using a larger unit like a meter or kilometer would result in a measurement that is too large and not precise enough for the small size of the pencil tip.
- On the other hand, using smaller units like micrometers or nanometers would be unnecessarily precise for measuring the tip of a pencil, as these units are typically used for much smaller objects, such as cells or molecules.
- Therefore, the millimeter is the most appropriate unit for measuring the tip of a pencil as it provides a good balance between precision and practicality for this particular measurement.