Measurement of Length and Motion
Fill in the Blanks:
1. The SI unit of length is the ______.
Answer: metre
2. A metre is divided into 100 equal parts, and each part is called a ______.
Answer: centimetre
3. ______ is used to measure very large distances, like the distance between cities.
Answer: Kilometre
4. The motion of a swing is called ______ motion.
Answer: oscillatory
5. ______ motion is when an object moves along a straight path.
Answer: Linear
6. One centimetre is equal to ______ millimetres.
Answer: 10
7. The position of an object is described with respect to a fixed point called a ______.
Answer: reference point
8. The distance between two points is measured using the unit called ______.
Answer: metre
9. In the International System of Units (SI), ______ is used for measuring very small lengths.
Answer: millimetre
10. A merry-go-round is an example of ______ motion.
Answer: circular
True / False:
1. A kilometre is smaller than a metre.
Answer: False (A kilometre is larger; 1 km = 1000 metres)
2. Linear motion means moving in a straight line.
Answer: True
3. The handspan is a reliable method of measuring length.
Answer: False (It varies from person to person)
4. The SI unit of length is the inch.
Answer: False (The SI unit is the metre)
5. An object at rest has no motion with respect to its reference point.
Answer: True
6. Oscillatory motion is the movement of an object in a circular path.
Answer: False (Oscillatory motion is to and fro movement)
7. The motion of a car on a straight road is an example of circular motion.
Answer: False (It is an example of linear motion)
8. One metre is equal to 1000 millimetres.
Answer: False (1 metre = 1000 millimetres)
9. A pendulum in a clock shows oscillatory motion.
Answer: True
10. The measurement of curved lines can be done using a thread.
Answer: True
Question / Answers
1. What is the need for standard units of measurement?
Answer: Different body parts (e.g., handspan, foot) vary in size from person to person. To ensure consistent and accurate measurements, standard units like metres are needed so measurements do not differ.
2. What is the SI unit of length and its symbol?
Answer: The SI unit of length is the metre (m).
3. How is a metre divided into smaller units?
Answer: A metre is divided into 100 centimetres (cm), and each centimetre is further divided into 10 millimetres (mm).
4. How would you measure the length of a curved line?
Answer: To measure a curved line, you can use a thread to follow the curve and then measure the length of the thread with a ruler.
5. What is a reference point? Why is it important in measuring position?
Answer: A reference point is a fixed location used to compare and describe the position of objects. It is important because it helps to define whether an object is at rest or in motion relative to that point.
6. What do you mean by motion?
Answer: An object is said to be in motion if its position changes over time relative to a reference point.
7. What are the different types of motion?
Answer: The three main types of motion are:
- Linear Motion: Movement in a straight line.
- Circular Motion: Movement in a circular path.
- Oscillatory Motion: Back-and-forth movement around a fixed point.
8. What is linear motion? Give an example.
Answer: Linear motion is when an object moves along a straight path. Example: A train moving on a straight track.
9. What is circular motion? Give an example.
Answer: Circular motion is when an object moves in a circular path. Example: The rotation of the Earth around the Sun.
10. What is oscillatory motion? Give an example.
Answer: Oscillatory motion is when an object moves to and fro around a fixed point. Example: The motion of a pendulum in a clock.
11. How should we place a scale to measure length accurately?
Answer: The scale should be placed along the length of the object, ensuring that one end of the object is aligned with the zero mark on the scale.
12. What should be done if the zero mark on a scale is broken?
Answer: If the zero mark is broken, start measuring from another clear mark (such as 1 cm) and subtract that value from the total measurement.
13. What is the difference between centimetres and millimetres?
Answer: 1 centimetre (cm) is equal to 10 millimetres (mm). Centimetres are used to measure slightly larger lengths, while millimetres are used for very small measurements.
14. How can we measure very large distances?
Answer: Very large distances, such as between cities, are measured in kilometres (km). 1 kilometre = 1000 metres.
15. What is the relationship between motion and a reference point?
Answer: Motion is determined by comparing an object’s position to a reference point. If the object’s position changes relative to the reference point, the object is said to be in motion. If the position doesn’t change, it is at rest.
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