Short & Long Question Answers: Measurement of Length and Motion | Science for Class 6 PDF Download

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Short Answer Type Questions

Q1. Give two examples of rotational motion.
Ans: Examples of rotational motion include:

• The motion of a wheel, gears, and motors.
• The motion of the blades of a fan.

Q2. What is the significance of the metre in the International System of Units?
Ans: The metre is the fundamental unit of length in the International System of Units (SI). Its significance includes:

• Essential for both scientific and everyday measurements.
• Facilitates global communication and understanding in various fields.

Q3. How can you measure the length of a Curved line accurately?
Ans: To measure the length of a curved line accurately, follow these steps:

• Use a flexible measuring tape or a piece of thread.
• Carefully place the tape or thread along the curve.

Measuring Tape

Ans: A reference point is a fixed location used to determine the position of another object. It serves as a consistent basis for measuring distances and positions. 

• Helps in accurately measuring distances.
• Essential for identifying whether an object is in motion or at rest.

For example, if you state your distance from a landmark, that landmark acts as your reference point.

Q5. Why are flexible measuring tapes preferred for measuring the girth of objects?
Ans: Flexible measuring tapes are preferred for measuring the girth of objects due to their ability to conform to shapes. Here are the key reasons:

• They can easily wrap around curved surfaces.
• This flexibility ensures accurate measurements of irregularly shaped objects.
• They are more practical than rigid measuring tools for such tasks.

Q6. What do you and your friends discover when you compare the handspans?
Ans: We found that our handspans vary in size, resulting in different measurements for the same object. This shows:

• Body parts are not consistent for measuring.
• There is a need for standard units to ensure accuracy.
• Using scales and measuring tapes is more reliable.

For example, if the table's length is measured in handspans, it can differ based on each person's handspan size.

Handspans

Ans:Oscillatory motion differs from linear and circular motion in several ways:

• It involves an object moving back and forth around a fixed point.
• Linear motion is movement along a straight path.
• Circular motion involves movement along a circular path.

Q8. Why do we not use a footstep as a standard unit of length?
Ans: The length of a footstep varies from person to person, making it an unreliable standard unit of measurement. Key points include:

• A footstep is not consistent across individuals.
• This inconsistency leads to confusion in measurements.
• Standard units, like the metre, provide uniformity.

Footstep

Long Answer Type Questions

Q1. Why is it important to use standard units of measurement in everyday life?
Ans: Using standard units of measurement in everyday life is crucial for several reasons:

• Consistency: Standard units ensure that measurements are uniform across different contexts.
• Accuracy: They help in obtaining precise measurements, reducing the chance of errors.
• Clear Communication: Standardised measurements facilitate better understanding and comparison.
• Reliability: In fields like science, engineering, and trade, standard units are essential for dependable results.

Q2. How the measurements using body parts to measure length were considered inconsistent?
Ans: Using body parts to measure length is often inconsistent for several reasons:

• Different individuals have varying sizes of body parts, such as handspans, foot spans, and strides.
• For example, one person's handspan may be longer than another's, leading to different measurements.
• This variability highlights the need for standard units of measurement.

Q3. Define motion. What are different types of motion?
Ans: Motion is the process of changing position or moving from one place to another. The different types of motion include:

• Translational motion: Movement in the same direction covering equal distances over time.
• Linear motion: Movement along a straight line.
• Circular motion: Movement along a circular path.
• Rotational motion: Movement around an axis.
• Periodic motion: Movement to and fro about a fixed point.
• Vibratory motion: A fast back-and-forth movement.

Motion
Q4. Describe the process of using a thread to measure the length of a curved line.
Ans: To measure the length of a curved line using a thread, follow these steps:

• Place the thread along the entire curve, ensuring it follows the shape accurately.
• Mark the endpoints on the thread.
• Straighten the thread and measure it with a ruler or measuring tape.

This method provides an accurate measurement of curves, which cannot be measured with straight scales.

Q5. Explain the significance of the International System of Units (SI) and its impact on global measurements.
Ans: The International System of Units (SI) is crucial for several reasons:

• It provides a standardised set of measurement units used worldwide.
• Facilitates international trade and scientific collaboration.
• Ensures measurements are consistent and comparable across countries.
• Reduces misunderstandings and errors in communication.

The SI system includes essential base units such as:

• Metre (m) for length
• Kilogram (kg) for weight
• Second (s) for time