## Chapter - 10

Motion and Measurement of Distances

### NCERT MP Board Class 6 Science Chapter 10 Motion and Measurement of Distances

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### NCERT MP Board Class 6 Science Chapter 10 Motion and Measurement of Distances

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### NCERT MP Board Class 6 Science Chapter 10 Motion and Measurement of Distances

Solution

Page No 106:

**1. Give two examples each of modes of transport used on land, water, and air.**

**Ans.**Modes of transport used on land are - buses and cars.

Modes of transport used on water are -boats and ships.

Modes of transport used in air are -aeroplanes and helicopters.

**2. Fill in the blanks:**

**(i) One metre is ___________ cm.**

**(ii) Five kilometres is ___________ m.**

**(iii) Motion of a child on a swing is ____________.**

**(iv) Motion of the needle of a sewing machine is __________.**

**(v) Motion of wheel of a bicycle is____________.**

**Ans.**

(i) One metre is

__100__cm.(ii) Five kilometres is

__5000__m.(iii) Motion of a child on a swing is

__periodic__.(iv) Motion of the needle of a sewing machine is

__periodic motion__.(v) Motion of wheel of a bicycle is

__circular motion.__**3. Why can a pace or a footstep not be used as a standard unit of length?**

**Ans.**The size of the foot varies from person to person. If footsteps of two persons are used to measure the length, distances may not be equal. Therefore it cannot be used as a standard unit of length.

**4. Arrange the following lengths in their increasing magnitude:**

**Ans.**1 metre, 1 centimetre, 1 kilometre, 1 millimetre

Ans.

1 cm = 10 mm

1 m = 100 cm = 1000 mm

Again, 1 km = 1000 m = 100000 cm = 10000000 mm.

Hence, 1 mm is smaller than 1 cm, 1 cm is smaller than 1 m, and 1 m is smaller than 1 km, iSo

1 millimetre < 1 centimetre < 1 meree < 1 kilometre

**5. The height of a person is 1.65 m. Express this in cm and mm.**

**Ans.**Height of the person = 1.65 m

1 m = 100 cm

1.65 m = 100 × 1.65 = 165 cm

Hence, the height of the person is 165 cm.

Again, 1 m = 100 cm = 1000 mm

Therefore, 1.65 m = 1.65 × 10 = 1650 mm

Hence, the height of the person is 1650 mm.

**6. The distance between Radha’s home and her school is 3250 m. Express this distance in km.**

**Ans**. The distance between Radha’s home and her school is 3250 m.

1 km = 1000 m

i.e., 1000 m = 1 km

3250 m = 3250 × 1/1000 = 3.25 km

**7. While measuring the length of a knitting needle, the reading of the scale at one end is 3 cm and at the other end is 33.1 cm. What is the length of the needle?**

**Ans.**The reading of the scale at one end is 3 cm and at the other end is 33. 1 cm.

So, the length of the knitting needle is given by subtracting both the readings, i.e., (33.1− 3.0) cm = 30.1 cm.

**8. Write the similarities and the differences between the motion of a bicycle and a ceiling fan that has been switched on.**

**Ans.**Similarities between the motion of a bicycle and a ceiling fan:

(i) The blades of a fan and the wheels of a bicycle are fixed at a point.

(ii) Both have circular motion about their respective fixed points.

Differences between the motion of a bicycle and a ceiling fan:

(i) A bicycle has linear motion, whereas the blades of a ceiling fan do not have linear motion.

(ii) The motion of the blades of a fan is periodic, whereas the motion of a bicycle is rectilinear motion.

**9. Why can you not use an elastic measuring tape to measure distance? What would be some of the problems you would meet in telling someone about a distance you measured with an elastic tape?**

**Ans.**An elastic measuring tape is stretchable. It cannot be used to measure distances because the length of the tape may change on stretching. Due to this the measure would not be accurate.

**10. Give two examples of periodic motion.**

**Ans.**Examples of periodic motion are :

(i) Motion of Pendulum

The Bob of a pendulum repeats itself at a certain period of time, thus this type of motion is called periodic motion.

(ii) Motion of a boy sitting on a swing

This type of motion takes certain period of time to repeat itself hence this is also an example of periodic motion.