CBSE Class 9 - Force and Laws of Motion - What is Inertia? (#cbseNotes)

What is Inertia? 

CBSE Class 9 - Force and Laws of Motion 

Let's move the rock!

Inertia
It is inherent property of all bodies, by virtue of which it resists or opposes any change to it's present state of rest or of uniform motion. It varies directly as mass of the body.

Inertia of a body is of three types:

① Inertia of rest

It is in ability of a body to change by itself or if state of rest. This means a body at rest remains at rest and cannot start moving on its own.

② Inertia of motion

It is an ability of a body to change by itself its state of uniform motion that is a body in uniform motion can either accelerate no retard on its own and come to rest.

③ Inertia of direction

It is in ability of a body to change by itself its direction of motion

Exercise

Fill in the blanks:

⒈ When we shake a branch of a mango tree the mangoes fell down, this happens because of ___________.

⒉ An umbrella protects us from rain it is based on the property of _____________.

⒊ When a car enters a curved path, the person sitting in it is thrown outwards. This is because of the property of ______________.

⒋ It is dangerous to jump out of a moving bus because due to _________ one falls forward.

⒌ Which has more inertia of Cricket ball or a rubber ball of the same size? __________

⒍ On what factor does the inertia of a body depends? ____________

⒎ When a bus starts suddenly, the bus passengers standing in the bus tend to fall backwards. It is due to _______________.

⒏ When a passenger jumps out of moving bus, he falls down. It is due to _______________.

⒐ A cyclist on a levelled road does not come to rest immediately even he stops pedalling. It is due to ______________.

⒑ When the playing card is flicked with the finger the coin placed over it falls in the tumbler. It is due to ____________.

⒒ An athlete often jumps before taking a long jump. It is due to ________________.

⒓ ________ is a measure of intertia.

⒔ When a hanging carpet is beaten with stick, the dust particles start coming out of it. It is due to ______________.

⒕ ________ is the tendency of an object to resist a change in motion.

⒖ The property of an object to resist changes in its rotational state of motion is called ________.



Answers:

⒈ inertia of rest
⒉ inertia of direction
⒊ inertia of direction
⒋ inertia of motion
⒌ Cricket ball
⒍ Mass
⒎ Intertia at rest
⒏ Interia of motion
⒐ Interia of motion
⒑ Intertia at rest
⒒ Interia of motion
⒓ Mass
⒔ inertia of rest
⒕ Inertia
⒖ rotational inertia