ACTIVITY- 3 : To
measure the length of a curved line.
Question 1- The
length of a curved line can be measured by a metre scale directly. (True/False)
Answer- False.
Question 2- The
metre is standard unit of length. (True/False)
Answer- True.
EXERCISE
Question 1- Fill In
The Blanks.
a. One metre is 100
cm.
b. Five kilometer is 5000 m.
c. Motion of a child on a swing is periodic motion.
d. Motion of the needle of a sewing machine is periodic motion.
e. Motion of wheel of a bicycle is circular motion.
Question 2- Write
True Or False.
a. Hand span or feet step are standard units of
measurement. (False)
b. Standard unit of length is metre. (True)
c. Motion of train on railway track is an example of
linear motion. (True)
d. Length of a curved line can be measured by a scale.
(False)
e. Motion of hands of a clock is a circular motion. (True)
Question 3- Match
The Column ‘A’ With Column ‘B’.
A B
a. Metre a. Periodic motion (e)
b. Circular motion
b. Length (a)
c. 1 km c. Linear motion (d)
d. Train on track d. Hands of clock (b)
e. Swing e. 1000m (c)
Question 4. Choose
The Correct Answer.
(i). In motor
vehicles which of the following is used for measuring the distance covered by the vehicle?
a) Speedometer b) Odometer (✓) c) Thermometer d) None
of these
(ii). A student
want to take the measurements of a brick, for this purpose which unit he should use?
a) kilometre
b) metre
c) centimeter (✓)
d) Hand span
(iii). The
motion of wings of a moving fan is …………..
a) Circular motion (✓)
b) Linear motion
c) Both (a) and (b)
d) None of these
(iv). Which of
among is false?
a) 1000m = 1 km
b) 100 mm = 1cm (✓)
c) 100cm = 1m
d) 10mm = 1cm
Question 5- Very
Short Answer Type Questions.
(i) Name some
means of transport used in ancient time?
Answer- Animals like horses, carts, boats etc.
(ii) Give two
examples of periodic motion.
Answer- Motion of swing, motion of needles of clock.
Question 6- Short
Answer Type Questions.
(i) Give two
examples of transport used on land, water and air.
Answer- Land- Car, train, bicycle.
Water-
Boat, ship, submarine.
Air-
Airplane, helicopter, rocket.
(ii) What is
distance?
Answer- Distance is the length of space between two
points.
(iii) Arrange
the following lengths in their increasing magnitude:
1 metre, 1 centimetre, 1 kilometre, 1
millimetre.
Answer- 1 millimetre < 1 centimetre < 1 metre
< 1 kilometre.
(iv) Write the similarities and differences between
the motion of a bicycle and a ceiling fan that has been switched ON.
Answer- Similarity:
Both the ceiling fan and the wheels of a bicycle show circular motion.
Difference:
A bicycle shows linear motion while a ceiling fan does not.
(v) The
distance between Radha’s home and her school is 3250 m. Express this distance into km.
Answer- 3250 m = 3250/1000 = 3.25 km.
Question 7- Long
Answer Type Questio
(i) Describe
what precautions should be taken while measuring length or breadth of an object?
Answer- (1) We should use appropriate unit of length.
(2) One end of length should be parallel to zero of
scale.
(3) While taking reading position of eye should be
correct.
(ii) How many
types of motion are there? Give examples for each type.
Answer- Motion is generally of three types –
(1) Linear
Motion- Train of straight railway track, car on straight road.
(2) Circular
Motion- Motion of wings of fan, Motion of hands of clock.
(3) Periodic
Motion- Motion of swing, motion of needles of clock.
(iii) Write an
activity for measuring the length of a curved line?
Answer- Make a curved line AB on a chart. Make a knot
on one end (A) on a thread and place the knot on one end of curved line. Now
place thread on curved line by stretching in small portions up to the other end
(B) of curved line. Make another knot on the thread where it touches the point
B. Now stretch the thread along a meter scale and measure distance between two
knots. This is the length of given curved line.
(iv) Why hand
span or footsteps cannot be used as standard units of measurement?
Answer- Because length of hand span and footsteps vary
from person to person. So length measured by hand span or footsteps cannot be
same for different people. Hence we cannot use hand span or footsteps as
standard unit.
