Motion Basics
Understanding Motion:
❖ Definition: Motion is the change in position of an object over
time. In physics, motion can be defined and calculated using
a few variables that all bodies in motion have or can have:
velocity, acceleration, displacement, and time.
❖ Newton's Three Laws of Motion:
1. First Law of Motion: An object at rest remains at rest, and
an object in motion remains in motion at constant speed and
in a straight line unless an external force is applied to it. This
tendency to resist changes in a state of motion or rest is
inertia. If all the external forces cancel each other out, then
there is no net force acting on the object.
Application:
• Jumping from a moving car: When a bus starts moving all of a sudden, we feel a
sudden jerk and our foot moves faster than the rest of our body. This is because the
foot goes in a state of motion and the upper part of the body continues to be in a
state of rest.
• Dust particles from carpet: When a carpet is beaten with a stick, the dust particles
in the carpet which remained at the inertia of rest fall down due to gravity and
the state of motion which developed because of beating the carpet with a stick.
• Running a race: In a 500 m race, Raja reaches the finish line and wins the race but
he continues to run for some more meters because the legs are still in a state of
inertia of motion.
DID YOU KNOW?
Types of Inertia:
• There are basically three types of Inertia-
• Inertia of Rest: The inability of a body to change by itself its state of rest is known as
Inertia of Rest. Example: A pen is kept in the palm of a person and the man is asked
