Motion and Measurement of Distances Question Answers: NCERT Class 6 Science

Transportation is the method through which one object can move from one place to another through the transport. There are different modes of transport system on the basis of their requirement.

1. Land transport: All automobiles like car, buses, trucks, bicycle are the examples of land transport. 
2. Water transport: Ship, boat, water crafts are the examples of water transport.
3. Air transport: Aero-plane, helicopter, gliders are the examples of air transport.

(i) 100                                                                                                                                                                                                                                                 According to metric scale, 1 meter = 100 cm.

(ii) 5000                                                                                                                                                                                                                                                                  1 km = 1000 meter

5 km = 5 x 1000

= 5000 meter

(iii) Circular                                                                                                                                                                                                                              Motion that occurs in circle is known as circular motion.

(iv) Periodic motion                                                                                                                                                                                                                Motion that occurs after the same interval of time is known as periodic motion.

(v) Circular motion                                                                                                                                                                                                                 Motion that occurs in a circular path or when a body moves round and round called as it have circular motion.

A pace or a footstep not be used as a standard unit of length because its size of the foot can be increase with the time. Footsteps size is differ from person to person. So, it cannot be used as a standard unit of length.

1 mili-meter = 0.001 meter

1 kilometer = 1000 meter

1 centimeter = 0.01 meter

So, 1 mm < 1 cm. < 1 m. < 1 km

Height of the person is 1.65 meter.

• 1m. = 100 cm.                                                                                                                                                                                                               1.65  = 1.65 x 100                                                                                                                                                                                                                          100

            1.65 m. = 165 cm.

• 1 m. = 1000 mili- meter

           1.65 m = 165 x 1000 = 1650 mm                                                                                                                                                                                                                     100

Distance between Radha’s home and her school is 3250 meter.

1. 1 m = 0.001 km

3250 m = 3250 x   1     .                                                                                                                                                                                                                                                      1000

3250 m = 3.25 km.

Reading of the scale at one end = 3.0 cm

Reading of the scale at other end = 33.1 cm

Total length of the needle = 33.1 – 3.0

                                         = 30.1 cm.

Similarities between motion of bicycle and a ceiling fan:

Bicycle and ceiling fan both show circular motion. They both are fixed as wheel of bicycle is fixed as the ceiling fan.

Differences:

1. Both shows different motion when fan is switched on. Like bicycle shows rectilinear motion but ceiling fan shows the circular motion.
2. When a bicycle wheel rotates, movement from one place to another place occurs, whereas fan is fixed.

We could not use elastic tape to measure distance because due to elasticity its measurement is not accurate or we can say not approximate. An elastic tape is stretched when we hold it from one end. Sometimes its size is reversed. So, accurate measurement is not taken by an elastic tape.

A motion which occurs in a definite interval of times is called periodic motion. For example: needle of a sewing machine, a child on swing, needle of a clock etc.