Chapter 10
Motion and Measurement of Distances
I. Answer the following questions in brief:
Q.1. What type(s) of motion(s) does a ball rolling on the ground have?
Ans - The rolling ball on the ground shows rectilinear motion as well as rotational motion.
Q.2. Write the similarities and differences between the motion of the earth around the sun and the wheel of bicycle.
Ans - Similarities: The motion of the earth around the sun and the wheel of bicycle shows periodic motion.
Differences: The motion of the wheel of bicycle shows rectilinear motion which is not shown by motion at earth around the sun.
Q.3. The height of a tree is 783 cm. Express it in m and mm.
Ans - Given 783 cm
|
1 cm = 1 / 100 m 783/100 = 7.83 m |
1 cm = 10 mm 783 x 10 = 7830 mm |
Q.4. Which measuring device would you choose to measure the girth (thickness) of a tree trunk: metre rod or measuring tape? Why?
Ans - We choose a measuring tape because it can bend around the girth of a tree trunk so it is more suitable measuring device.
Q.5. What type of motion does the string of a guitar have?
Ans - The string of a guitar have periodic motion.
Q.6. The distance between Pooja's home and Charminar is 37281 m. Express this distance in km.
Ans - 1 Km = 1000 m
37281 / 1000 = 37.281 Km
Q. 7 While measuring the length of a sheet of paper, the reading of the scale at one end is 3.8 cm and at the other end is 17.5 cm. Find the length of the sheet.
Ans - 17.5 - 3.8 = 13.7 cm
II. Given one term for each of the following:
(a) Motion in which an object repeats its motion after some time. Periodic Motion
(b) Length of path between two places. Distance.
(c) Comparison of an unknown quantity with some known quantity. Measurement
(d) Type of motion in which the moving object remains at a constant distance from a fixed point. Circular Motion
(e) Motion in a straight line rectilinear motion
(f) Unit of length in SI units. Metre
III. Fill in the blanks:
(a) The French created the metric system in 1790.
(b) While taking measurement, the eye must be exactly in front of the point where the measurement is to be taken.
(c) A pendulum undergoes Periodic motion.
(d) 3.278 km = 3278 m.
(e) A ball rolling on the ground undergoes rectilinear as well as rotational motion.
(f) The proper device for measuring the girth of a tree is a measuring diameter tape.
IV. State whether True or False.
(a) 1234 cm = 1.234 km (False)
(b) A footstep is a standard unit of length. (False)
(c) A measuring tape is a suitable device for measuring the length of a curved line. (True)
(d) A scale with broken ends can be used to measure the length of a line. (True)
(e) An object cannot have more than one type of a motion at a time. (False)
(f) The needle of a sewing machine undergoes periodic motion. (True)
V. Given one term for each of the following:
(a) Table - Periodic motion
(b) 328 m - 328000 mm
(c) Bullock Cart - Animal Power
(d) Sprinter - Rectilinear motion
(e) 3.28 km - 328000 cm
(f) Rail engine - Steam power
VI. Choose the correct alternative:
(i) Motion of earth around the sun is an example of
Ans (a) periodic motion
(ii) 3258 cm =
Ans (a) 32.58 m
(iii) In the figure given below, the proper position of the eye for taking a reading of the scale is
Ans (b) B
(iv) You would measure the size of your chest using
Ans (b) measuring tape
(v) The pendulum of a clock undergoes
Ans (c) Periodic motion
(vi) In the figure given below, the length of the line XY is
Ans (c) 3.5 cm
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