2. Motion
Motion is some kind of a change in the position of an
object with time.
Fling Bird Moving train Fling plane
You might have noticed that the bird is not at the same place
after some time, while the table is at the same place.
On this basis you may have decided whether an object is at rest
or in motion.
3. The position variable
Motion is about knowing where things are and how
they move.
To understand where things are, we need to
understand position.
Position is a variable and it is always relative to an
origin, or the place where the object’s starting point
was zero.
4. Forward and backward
Position and distance are similar but not
the same. Both use units of length.
Distance can have only positive values.
Position uses positive and negative
numbers.
Positive numbers are for positions to the right (in front) of
the origin.
Negative numbers are for positions to the left (or behind) the
origin.
5. Forward and backward
Many variables can be positive or negative.
These include position, speed, and force.
These variables are called vectors because they can
have a value and a direction.
We use the term
velocity to mean
speed with direction.
6. Types of Motion
Rectilinear motion:
The objects move along a straight line is called the
rectilinear motion.
Example: motion of a vehicle on a straight road,
march-past of soldiers in a parade.
7. Circular motion is a movement of an object along
the circumference of a circle or rotation along a circular
path or a circular orbit.
Example : The motion of a point marked on the blade of
an electric fan or the hands of a clock are examples of
circular motion.
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8. Periodic motion:
An object repeats its motion after some time.
Motion of a pendulum, a branch of a tree moving to and
fro, motion of a child on a swing, strings of a guitar or
the surface of drums being played, are all examples of
periodic motion
