Chapter 10: Motion and Measurement of Distances

    I. Multiple Choice Questions (MCQs).
    Q.1. Which of the following arrangement is correct?
    a) 1 metre < 1 centimetre < 1 kilometre < 1 millimetre
    b) 1 millimetre < 1 centimetre < 1 metre < 1 kilometre c) 1 metre > 1 centimetre > 1 kilometre > 1 millimetre
    d) 1 millimetre > 1 centimetre > 1 metre > 1 kilometre

    Answer: b) 1 millimetre < 1 centimetre < 1 metre < 1 kilometre

    Q.2. Which invention has made a great change in mode of transport?
    a) Bicycle
    b) Scooter
    c) Wheel
    d) Rickshaw
    Answer: c) Wheel

    Q.3. Which of the following is not correct?
    a) The SI unit of electric current is ampere.
    b) Every object moves with a constant speed.
    c) Distances between two cities are measured in kilometres.
    d) The SI unit of time is second.

    Answer b) Every object moves with a constant speed.

    Q.4. The known constant quantity used in measurement is called a
    a) standard
    b) scale
    c) unit
    d) distance

    Answer: c) unit
    Q.5. The length of the outstretched arms is called
    a) Handspan
    b) cubit
    c) unit
    d) fathom
    Answer d) fathom

    II. Fill in the blanks by selecting appropriate words from the given list :
    List : periodic, rest, Transport, rectilinear, standard
    Q.1. _______________ simply means, to carry people or goods from one place to another by means of a vehicle, aircraft or ship.
    Q.2. The _______________ units are needed to measure physical quantities.
    Q.3. If the position of body does not change with respect to time and surroundings, the body is said at _______________.
    Q.4. When an object moves in a straight line, it is said to be in _______________ motion.
    Q.5. The motion which repeats itself after a certain fixed period of time, is called _______________ motion.
    1- Transport,
    2- standard,
    3- rest,
    4- rectilinear,
    5- periodic

    III. Match the items of Column A with those of Column B.

    Answer: 1- (c) , 2- (d), 3-(b), 4- (e) , 5-(a)

    IV. Write ‘T’ for the true and ‘F’ for the false statements.
    Q.1. There are so many occasions when we come across a need to measure lengths and distances.
    Q.2. The value of a standard unit does not change when used by different individuals.
    Q.3. One metre (m) is divided into 100 equal divisions, called millimetre.
    Q.4. The SI system has seven most common basic standard units used in our daily life.
    Q.5. It is impossible to measure the length of a curved line using a metre scale.

    Ans 1-T, 2-T, 3-F, 4-F, 5-T

    V. Very Short Answer Questions.
    Q.1. Write two means of transport used in ancient time.
    Answer: Bullock carts and boat

    Q.2. Define physical quantity.
    Answer: A physical quantity is any physical property that can be quantified, that is, can be measured using numbers.

    Q.3. Write the standard units of mass, length and time used in SI system.

    Q.4. Write two multiples of metre.
    Answer: Hectometre and kilometre
    Q.5. Write two submultiples of metre.
    Answer: Centimetre and Millimetre
    Q.6. How can you measure the height of your classmate?
    Answer: To measure the height of my classmate, I will ask my classmate to stand with his back against a wall. I will make a mark with pencil over his head. Now, by using the tape, I will take the length (height) of my classmate from ground level to the position of marked on the wall.

    Q.7. Define state of rest with examples.

    Answer: “An object is at rest if its position does not change with time in relation to a stationary object”. For example house, tree, etc. doesn’t change their position so they are at rest.

    Q.8. Define motion with examples.

    Answer: An object is in motion if its position changes with time in relation to a stationary object such as a building or a tree, etc. For example when the position of a car changes with time, we say that the car is moving or the car is in motion.

    VI. Short Answer Questions.
    Q.1. Discuss story of transport in your own words.
    Answer: In ancient time there was hardly any mode or means of transport. Neither steam engine nor wheel was invented. So their means of transport was manual or physical. They used domestic animals, bullock carts, country boat, etc., to carry goods as well as travel from one place to another. But the invention of the wheel made a great change in modes of transport. Vehicles that moved on wheels pulled by animals were used to travel from one place to another. But with the invention of steam engine, aeroplanes, and spacecraft in transport has been solved to a great extent.

    Q.2. How can you say need for measurement must have arisen out of everyday activities? Explain with suitable examples.

    Answer: The tailor needs to measure the length of the cloth according to requirement of fitting. If carpenter was there to make a wooden door you would need its length and breadth of the door to calculate how much wood be required to make the door. From the above discussion it is clear that need for measurement must have arisen out of everyday activities.

    Q.3. Vikram’s height is 1.22 m. Calculate Vikram’s height in centimetre.
    Answer: Vikram’s height = 1.22 m
    We know that 1 m = 100 cm
    So, Vikram’s height(in cm) = 1.22 × 100 = 122 cm

    VII. Long Answer Questions.
    Q.1. Discuss how to measure a curved line stepwise. Explain all such precautions which needed for this measurement.

    Answer: It is very difficult or impossible to measure the length of a curved line or curved surface using a metre scale. You can do so easily by using a thread or divider. Put a knot on the thread at one end of the curved line, at point A. Now place a small portion of the thread along the line, keep it tight using your finger and thumb. Now hold the thread at this end point. Using other hand, pull a little more portion of the thread along the curved line. Repeat this process till the other end at point B of the curved line is reached. Now mark the thread where it touches the end B. Now stretch the thread along a metre scale. Measure the length between A and B, which gives the length of the curved line AB.

    Some precautions you should take while measuring length:
    (a) Keep the ruler along the length of the object.
    (b) If the edge of the ruler is worn-out or broken, the measurement should be started from any other clear mark.
    (c) Correct position of the eye is also important for taking measurement.

    Q.2. (a) The distance between Shruti’s home and her school is 5050 m. Calculate this distance in kilometre.
    (b) Vikram bought 2250 g vegetable from a vegetable shop. Calculate the mass of the vegetables in kilogram.

    Answer: (a) Distance between Shruti’s home and her school = 5050 m
    We know that 1000 m = 1 km
    So, 5050 m = 5050/ 1000 = 5.05 km
    Distance between Shruti’s home and her school = 5.05 km

    (b) Mass of vegetable = 2250 g We know that 1000 g = 1 kg

    So, 2250 g = 2250/ 1000 = 2.250 kg

    Q.3. Write all kinds of motion and discuss three of them properly.

    Answer: Different types of motion are
    i. Translatory motion
    a. Rectilinear motion :
    b. Curvilinear motion ii. Rotational Motion
    iii. Oscillatory Motion iv. Vibratory Motion
    v. Periodic and non-periodic Motion
    vi. Random motion

    Translatory Motion: All parts of the moving object also move through the same distance in the same interval of time as the whole object does. This type of motion of an object is known as translatory motion. Example of translational motion are an apple falling from the tree, a train moving on straight track, etc.

    Rotational Motion: A motion in which a body moves about a fixed axis without changing its position is called rotational motion. Example of rotational motion are motion of the blades of the table fan rotate and the hands of a clock.

    A body that moves about in a haphazard manner in all directions is called random motion. Examples of random motion are motion of houseflies, or of the players and the ball in a football or hockey game.

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