NCERT Class 6 Science Chapter 5 Measurement of Length and Motion Important Extra Questions and Answers

Very Short Answer Type Questions

Question 1.
What is the SI unit of length?
Answer:
Metre

Question 2.
How many centimetres are there in a metre?
Answer:
100

Question 3.
How many millimetres are there in a centimetre?
Answer:
10

Question 4.
What body part do you and your friends use to measure the table?
Answer:
Handspan

Question 5.
What flexible tool can be used to measure the girth of a tree?
Answer:
Tape

 

Question 6.
What is the unit used to measure long distances between different cities?
Answer:
Kilometre

Question 7.
What type of motion is exhibited by a swing?
Answer:
Oscillatory

Question 8.
What is the smallest value that can be measured using a typical 15-cm scale?
Answer:
Millimetre

Question 9.
Which ancient Indian unit of measurement is mentioned as still being used by traditional craftspeople?
Answer:
Angula

Question 10.
What is the reference point used by a traveller to determine how close she/he is to Delhi?
Answer:
Delhi

Question 11.
Define a unit.
Answer:
A unit is a comparison of an unknown quantity with that of a known quantity.

Question 12.
Anil and his friend measured the length of the same classroom using their feet. Will their measurements be the same? Explain your answer.
Answer:
The measurement of Anil and his friend will not be same as the length of their feet is not same.

Question 13.
Jenny wants to measure the height of her son. She asks her son to stand against a wall. Which picture shows the correct way of marking his height?

Answer:

Explanation: Picture B shows the correct way of marking the height as there is no parallax in this method.

Short Answer Type Questions

Question 1.
Why do people use standard units of measurement instead of body parts?
Answer:
People use standard units of measurement instead of body parts, because body parts vary in size from person to person, leading to inconsistent measurements. Standard units ensure that measurements are uniform and accurate regardless of who performs the measurement.

Question 2.
What is the significance of the metre in the International System of Units?
Answer:
The metre is an important International System of Units as it is the base unit of length. It provides a consistent standard for measuring length, which is essential for scientific and everyday measurements.

Question 3.
How can you measure the
length of a Curved line accurately?
Answer:
To measure the length of a curved line accurately, you can use a flexible measuring tape or a thread. Place the thread along the curve, then measure the length of the thread against a straight scale.

Question 4.
Explain the concept of a reference point in measuring distance.
Answer:
A reference point is a fixed object or location used to describe the position of another object. It helps in determining distances and positions accurately by providing a consistent point of comparison.

 

Question 5.
How does the position of the eye affect the accuracy of measuring with a scale?
Answer:
The position of the eye affects the accuracy of measuring with a scale because if the eye is not directly above the measurement mark, it can cause a parallax error. This error occurs when the measurement is viewed from an angle, leading to an incorrect reading.

Question 6.
Why are flexible measuring tapes preferred for measuring the girth of objects?
Answer:
Flexible measuring tapes are preferred for measuring the girth of objects because they can easily wrap around curved surfaces. This flexibility allows for accurate measurements of objects with irregular shapes.

Question 7.
What do you and your friends discover when you compare the handspans?
Answer:
We discover that our handspans are different in size, leading to varying measurements of the same object. This highlights the inconsistency of using body parts for measurement and the need for standard units.

Question 8.
How is oscillatory motion different from linear and circular motion?
Answer:
Oscillatory motion is different from linear and circular motion in that it involves an object moving to and fro about a fixed position. Linear motion involves movement along a straight path, while circular motion involves movement along a circular path.

 

Question 9.
Describe the process of measuring an object using a scale with broken ends.
Answer:
To measure an object using a scale with broken ends, you can start from a full mark on the scale instead of the zero mark. Measure the length from this point and subtract the initial reading to get the correct length.

Question 10.
How can you measure the distance between two places using a bicycle?
Answer:
To measure the distance between two places using a bicycle, attach a flexible metal strip to the wheel spoke to count the number of rotations. Measure the circumference of the wheel, multiply it by the number of rotations, and calculate the total distance travelled.

Question 11.
The photograph given as Fig. shows a section of a grill made up of straight and curved iron bars. How would you measure the length of the bars of this section, so that the payment could be made to the contractor?

Answer:
The length can be measured using a thread which can be further measured with the help of a scale.

Question 12.
Three students measured the length of a corridor and reported their measurements. The values of their measurements were different. What could be the reason for difference in their measurements? (Mention any three)
Answer:
Some of the reasons for difference in their measurement could be:

1. Different measuring devices were used.
2. The smallest length that could be measured by different devices may be different.
3. Measurement may not be along the shortest length in all three cases.
4. The end of the corridor may not be easily accessible.

Question 13.
Why do we not use a footstep as a standard unit of length?
Answer:
Since, the length of a footstep varies for every individual, a footstep cannot be used as a standard unit of length.

Question 14.
Give two examples of rotational motion.
Answer:
(a) The motion of the wheel, gears, motors, etc.
(b) The motion of the blades of a fan.

Question 15.
What is the way to ascertain whether an object is in motion or at rest?
Answer:
An object is said to be at rest when it does not change its position with time, while an object is said to be in motion when it changes its position with time.

Question 16.
Circle ‘Yes’ or ‘No’ for the correct response. Which of these could Jenny use to measure her son’s height?

Answer:
(i) Yes
(ii) No
(iii) Yes

Question 17.
Can the length of the pipe be measured correctly with a ruler? Explain your answer.

Answer:
The length of the pipe cannot be measured correctly with a ruler because the pipe is not straight, it is curved.

Long Answer Type Questions

Question 1.
Why is it important to use standard units of measurement in everyday life?
Answer:
It is important to use standard units of measurement in everyday life to ensure consistency, accuracy, and reliability. Standard units allow for clear communication and comparison of measurements, which is important in fields such as science, engineering, and trade. Without standard units, measurements would vary widely depending on the person taking the measurements. It leads to confusion and errors.

Question 2.
How the measurements using body parts to measure length were considered inconsistent?
Answer:
It was observed that using body parts to measure length was inconsistent by comparing the handspans, foot spans or strides etc.. Each person’s handspan resulted in a different measurement, demonstrating that body parts vary in size from person to person. This observation highlighted the need for standard units.

Question 3.
Describe the process of using a thread to measure the length of a curved line.
Answer:
To measure the length of a curved line using a thread, we first place the thread along the entire length of the curve, ensuring it follows the shape precisely. After marking the endpoints on the thread, we straighten the thread and measure it against a straight ruler or measuring tape. This method gives accurate measurement of curves, which cannot be measured with rigid straight scales.

Question 4.
Explain the significance of the International System of Units (SI) and its impact on global measurements.
Answer:
The International System of Units (SI) is significant because it provides a standard set of measurement units used globally, facilitating international trade, scientific studies, and technological development. By using SI units, countries can ensure that measurements are consistent and comparable, reducing misunderstandings and errors. The SI system includes base units like the metre (for length), kilogram (for weight), and second (for time), which are fundamental to various scientific and practical applications.

 

Question 5.
Write the correct techniques for measuring length accurately. Explain why are they important?
Answer:
Correct techniques for measuring length include placing the scale in contact with the object, aligning the scale properly along the object’s length, and positioning the eye directly above the measurement mark to avoid parallax errors. These techniques are important to ensure accuracy and consistency in measurements. For example, measuring a pencil with a broken scale requires starting from a full mark and subtracting the initial reading to obtain the correct length.

Question 6.
Discuss the historical units of measurement used in India and their relevance in modem times.
Answer:
Historical measurement units used in India, such as angula (finger width) and dhanusa (bow length), played a significant role in ancient architecture, town planning, and trade. These units are mentioned in ancient literature and are still used by traditional craftspeople like carpenters and tailors. Understanding these units provides insight into India’s rich history of measurement and how it has evolved to incorporate modern standard units.

Question 7.
How does the concept of a reference point help in accurately describing the position of an object?
Answer:
The concept of a reference point is important for accurately describing the position of an object because it provides a fixed location from which measurements can be made. For example, when we see kilometre stones indicating distances from D6lhi, Delhi acts as the reference point. Without a reference point, it would be difficult to determine precise locations and distances, which is essential for navigation, construction, and various scientific studies.

Question 8.
Describe an activity that demonstrates the difference between using body parts and standard units for measurement.
Answer:
An activity to demonstrate the difference between using body parts and standard units for measurement involves measuring the length of a classroom table using both methods. First, students can use their handspans and record the results, which will likely vary due to differences in hand size. Then, using a standard measuring tape or ruler, they can measure the table again, showing that standard units provide consistent and reliable measurements regardless of the measurer.

 

Question 9.
What is an Si unit? Give SI units of important measurements. Write the advantages of SI units over traditional units of measurement.
Answer:
The standard system of units is called the SI system (Système International d’unités in French). The SI units for measuring length, mass and time are metre (m), kilogram (kg) and second (s), respectively. SI units are based on the MKS (metre for length, kilogram for mass, second for time) system of units.
Advantages of the SI system:

• Universally accepted standardised set of units.
• Even very small measurements are possible in this system.
• The units do not change with time.

Question 10.
Define motion. What are different types of motion?
Answer:
Motion is the activity or process of continually changing position or moving from one position to another. Following are the different types of motions:

• When an object moves in the same direction and covers an equal distance in a given interval of time, then such motion is called translational motion.
• When a body moves along a straight line then it is called linear or rectilinear motion.
• When an object moves along a circular path, it is said to be in a circular motion.
• When an object moves about its axis, it is called rotational motion.
• When an object moves to and fro about a fixed point, it possesses periodic motion.
• A very fast back-and-forth motion is called vibratory motion.
• When a body moves in different directions and does not have a fixed path, it is called random motion.