Question

2. Fill in the blanks:
CM.
(i) One metre is
(ii) Five kilometre is
(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​

Answer 1

1. 1m = 100cm

2. 5km = 5000m = 500000cm

3. oscillatory

5. circular

Answer 2

Answer:

(I) 100 cm

(II) 5000 m

Explanation:

: Motion which repeats itself after certain intervals is called periodic motion. Since the motion of a swing also repeats after regular intervals so, the motion of the child on a swing is periodic.

(iv) The motion of the needle of a sewing machine is periodic.

Explanation: The needle of a sewing machine while moving up and down, repeats its motion after regular intervals so it possesses periodic motion.

(v) The motion of the wheel of a bicycle is circular.

Explanation: When an object moves in such a way that its distance from a fixed point remains the same, it is said to have circular motion. Since, the wheel of a bicycle rotates about its central part which remains fixed as the bicycle moves hence, the wheel possesses circular motion.