Class 6 Science Chapter 7 Practice Question Answers - Motion and Measurement of Distances

Q1: How can the length of any curved line be determined?
Ans: We must use a divider to determine the length of curved lines. Imagine a curved line AB. Open the divider’s legs to a convenient distance, such as 5 mm. At one end of the curving line, place one of the divider’s legs. Add the second leg to the line. Now determine how many times the divider must be moved along the line to completely cover line AB. Some of the line at the end, which is shorter than the separation between the two legs, may be omitted. By adjusting the divider, measure it separately. Multiply the distance between the two legs by the total number of full steps. To this length, add the length of the remaining distance. The length of the entire curved line will be obtained.

Q2: Define rest and motion.
Ans:

• Rest: If a body does not change its position with respect to its surroundings, the body is said to be at rest.
• Motion: A body is said to be in motion if it changes its position with respect to its surroundings.

Q3: Why is the standard unit for measurement necessary?
Ans: To improve the reliability and accuracy of our judgement, we need a standard unit of measurement. For proper dealing, everyone’s measurement should be the same.As a result, the measurement should be consistent. For the sake of uniformity, we require a standardised set of measurement units, known as standard units. Today, practically all fields of research and technology employ SI units.

Q4: Give two examples of periodic motion.
Ans:

• A swing in motion
• Motion of pendulum clock.

Q5: What is translatory motion? What are its types?
Ans: Translatory motion is a sort of movement in which every portion of the body moves the same distance in a specific amount of time.
Translatory motion is of three types:

• Linear motion
• Random motion
• Curvilinear motion.

Q6: Radha’s house is 3250 metres away from her school. Convert this distance to km.
Ans: 1 km = 1000m
3250 m = 3250 / 1000 = 3.250 km
Thus, the distance between Radha’s home and her school is 3.250 km.

Q7: Give two examples of linear motion.
Ans:

• Motion of a bike on a straight road.
• An athlete running on a straight track.

Q8: If you are sitting in a moving bus, are you at rest or in motion?
Ans: If we are seated in a bus that is moving, our position in relation to the objects inside the bus does not change. We are not moving in accordance with the definition of motion. The bus is moving. In other words, we can also say that we are stationary compared to everything within the bus and in motion compared to outside trees and other buildings.

Q9: Mention the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on.
Ans: (i) Similarity: Both a ceiling fan and a bicycle wheel display motion on a fixed axis.
(ii) Dissimilarity: A fan does not exhibit rectilinear motion, whereas a bicycle moves forward and executes this motion.

Q10: Mention the types of motion in which a body moves along a straight path.
Ans: Rectilinear or linear motion is the type of motion in which a body moves along a straight path.

Q11: The person’s height is 1.65 m. Convert it to cm and mm.
Ans: (a) 1.65 m
100 cm = 1 m
= 1.65 x 100
= 165 centimetre
(b) 65 x 100 x 10 mm = 1650 mm.

Q12: Using a thread, how will you find the circumference of a one-rupee coin?
Ans: Fix one end of the thread first, then position the coin next to it and roll the thread precisely once around the coin. Then, using a scale, determine the thread’s length to determine the needed coin circumference.

Q13: What are the reasons for recommending the SI system?
Ans: Reasons for recommending SI systems include:

• With this method, even very small measurements are achievable.
• It is a standardised unit; therefore, it is accepted universally.
• The calculation is made simple by system interconversions.
• The units are not affected by time or location.

Q14: State two precautions which should be taken while using a metre scale to measure the length of an object.
Ans:

• Along the object’s length, place the scale in contact with it.
• The eye must be correctly positioned above the place to be measured in order to take an accurate measurement, which is crucial.

Q15: While travelling on a train, it appears that the trees near the track are moving, whereas the co-passengers appear to be stationary. Explain the reason.
Ans: The trees appear to be moving in the opposite direction when we look out the window of a moving train because they are shifting their position with respect to us. Co-passengers, on the other hand, appear to be stationary because their location in relation to us is not moving.

Q16: Name the two parts that must be mentioned to state the measurement results.
Ans: Unit and magnitude are the two parts that must be mentioned to state the measurement results.

Q17: Why can’t a pace or a footstep be used as a standard unit of length?
Ans: A pace or a footstep can not be used as a standard unit of length because the pace or  footstep of each and every person is not equal.

Q18: Give two examples of each mode of transport used on land, water, and air.
Ans:

• Land: Bus, train, bike
• Water: Boat, ship
• Air: Aeroplane, Helicopter.

Q19: What is the expansion of the SI unit?
Ans: International System of the unit.

Q20: What is meant by rectilinear motion? Give two examples.
Ans: Any motion in which objects move in a straight line is known as rectilinear motion. Examples: Motion of any vehicle on a straight road, a moving train