NEWTON’S LAWS OF MOTION
INERTIA
➢ Is the property of an object at rest that causes it to remain at rest
OR
➢ Is a resistance an object has to change its state of motion
❖ If you were standing in a moving bus and its brakes were applied suddenly, you would fall forward.
This is because, your body wants to continue in the forward motion but the feet are forced to stop.
❖ On the other hand, if you were standing in a stationary bus and it is suddenly move forward you would fall backward, This is because your body wants to continue in its position of rest where as your feet are forced to a forward motion,
❖ Those phenomena are as a result of a property known as inertia. Bodies tends to keep on doing what
they are doing
Hence;
➢ Inertia also can be defined as the properties of a body to remain in motion in a straight line or at rest
unless acted upon by an external force
NOTE:
The inertia of an object is proportional to its mass. Thus the greater the mass of an object, the more it
resists change in its motion.
TYPES OF INERTIA
1. Inertia of rest
2. Inertia of motion.
3. Inertia of direction
1. INERTIA OF REST
➢ Is the resistance of a body to change its state of rest
➢ A stationary body requires force to make it move.
2. INERTIA OF MOTION
➢ Is the resistance of a body to change its state of motion
❖ A passenger sitting in a bus tends to fall forward when the bus suddenly stops because the lower part of his or her body comes to rest earlier than the upper part. Inertia tends to keep him or her moving.
3. INERTIA OF DIRECTION
➢ Is the resistance of a body to change its direction of motion
❖ For instance; mud from the wheels of a moving vehicles flies off tangentially (its follows the straight pass tangent to the wheel at the point of leaving).
❖ Also; when a stone lay on the sheet of paper on table, the stone remain at rest on the top of the table
when the paper was removed suddenly. This means that the stone tried to maintain its states of the rest
on top of the table. This demonstrates the force of inertia.
NEWTON’S FIRST LAW OF MOTION
It states that:
‘’Everybody continues in its state of rest or uniform motion in a straight provided that no
external force acts on it to change that state”
OR
It can be also state that:
‘’A body in motion continues in motion at a constant speed in a straight line and that at
rest remains so unless it is acted on by an external force”
