In the speed graph to the right, how many meters has the object moved after 10 seconds?
Answers
Answer:
I
n Class VI, you learnt about different
types of motions. You learnt that a
motion could be along a straight line,
it could be circular or periodic. Can you
recall these three types of motions?
Table 13.1 gives some common
examples of motions. Identify the type
of motion in each case.
13.1 SLOW OR FAST
We know that some vehicles move faster
than others. Even the same vehicle may
move faster or slower at different times.
Make a list of ten objects moving along
a straight path. Group the motion of
these objects as slow and fast. How did
you decide which object is moving slow
and which one is moving fast?
If vehicles are moving on a road in
the same direction, we can easily tell
which one of them is moving faster than
the other. Let us look at the motion of
vehicles moving on a road.
Activity 13.1
Look at Fig. 13.1. It shows the position
of some vehicles moving on a road in
the same direction at some instant of
time. Now look at Fig. 13.2. It shows the
position of the same vehicles after some
time. From your observation of the two
figures, answer the following questions:
Which vehicle is moving the fastest
of all? Which one of them is moving the
slowest of all?
The distance moved by objects in a
given interval of time can help us to
decide which one is faster or slower. For
example, imagine that you have gone to
see off your friend at the bus stand.
Suppose you start pedalling your bicycle
at the same time as the bus begins to
Table 13.1 Some examples of
different types of motion
Example of Type of motion
motion Along a straight
line/circular/
periodic
Soldiers in a
march past
Bullock cart
moving on a
straight road
Hands of an
athlete in a race
Pedal of a bicycle
in motion
Motion of the Earth
around the Sun
Motion of a swing
Motion of a
pendulum
It is common experience that the
motion of some objects is slow while that
of some others is fast.