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Lesson - 10, , (Motion and measurement of distances), , Q1. Fill in the blanks:, (i) One metre is 100 cm., , (ii) Five kilometre is 5000 m., (iii) Motion of a child on a swing is periodic., (iv) Motion of the needle of a sewing machine is periodic., (v) Motion of the wheel of a bicycle is circular., , Q2. Arrange the following lengths in their increasing magnitude: 1, metre, 1 centimetre, 1 kilometre, 1 millimetre., , Ans : 1 millimetre, 1 centimetre, 1 metre, 1 kilometre., Q3. The height of a person is 1.65 m. Express it into cm and mm., Ans : 1.65= 165 cm = 1650 mm, , Q4. The distance between Radha’s home and her school is 3250, m. Express this distance into km., , Ans :1km = 1000 m, Hence 3250 m = 3.25 km, , Q5. While measuring the length of a knitting needle, the reading of, the scale at one end is 3.0 cm and at the other end is 33.1 cm., What is the length of the needle?, , Ans : Length of needle = 33.1 - 3 = 30.1 cm.

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Q6. What is periodic motion. Give two examples of periodic, motion., , Ans : An object repeats its motion after some time. This type, of motion is called periodic motion., , This are the two example:, a) A needle of a sewing machine, b) Pendulum., , Q7. Give two examples each, of modes of transport used on land,, water and air., , Ans : Land- Train, Bus, Water- Ship, Boat, Air- Helicopter, Aeroplane., , Q8. Write the similarities and differences between the motion of, a bicycle and a ceiling fan that has been switched on., , Ans : Similarities - The blades of a fan and the wheels of a, bicycle shows circular motion, , Differences- Bicycle move in rectilinear motion, but the, fan does not move in rectilinear motion.