Mass and Inertia

11.4

Mass and Inertia

Mass

Mass: the quantity of matter in an object

S.I. unit = kilogram (kg)
Mass of an object is constant if the quantity of matter in an object does not change

Inertia

Inertia: the natural tendency of an object to resist any change in its original state, whether at rest or in motion

Cannot be measured

Newton's First Law of Motion states that an object will remain in its original state, that is, being at rest or in motion with constant speed if no external force acts on it

The inertia of an object is affected by its mass:

The larger the mass of an object, the larger the inertia of the object
The smaller the mass of an object, the smaller the inertia of the object

Effect of inertia in daily life

Positive effect	Negative effect
The loose head of a hammer can be tightened by banging its handle against a hard surface A wet umbrella can be dried by spinning the umbrella quickly	Can cause injury to car drivers During landing, an aeroplane cannot stop within a short distance

Mass and Inertia

11.4

Mass and Inertia

Mass

Mass: the quantity of matter in an object

S.I. unit = kilogram (kg)
Mass of an object is constant if the quantity of matter in an object does not change

Inertia

Inertia: the natural tendency of an object to resist any change in its original state, whether at rest or in motion

Cannot be measured

Newton's First Law of Motion states that an object will remain in its original state, that is, being at rest or in motion with constant speed if no external force acts on it

The inertia of an object is affected by its mass:

The larger the mass of an object, the larger the inertia of the object
The smaller the mass of an object, the smaller the inertia of the object

Effect of inertia in daily life

Positive effect	Negative effect
The loose head of a hammer can be tightened by banging its handle against a hard surface A wet umbrella can be dried by spinning the umbrella quickly	Can cause injury to car drivers During landing, an aeroplane cannot stop within a short distance

Mass and Inertia

Mass and Inertia

Chapter : Force and Motion

Topic : Mass and Inertia

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