Intro to Physics – Matter & Energy

http://www.aplusphysics.com/courses/honors/intro/matter_energy.html

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Objectives and Learning Targets

Understand the question, “What is Physics?”

Identify and explain several disciplines within the study of physics

Define mass, matter, work, and energy

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What is Physics?

Book definition has to do with…

matter

energy

interactions

But, the real question is “Why?”

Examples: Why is the sky blue? Why do objects fall?

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Matter…

Matter – anything that has mass and takes up space

Think of it as the amount of “stuff” in something

Examples of matter: solids (rocks, metals, etc.), liquids (water, vinegar, etc.), gases (helium, nitrogent, oxygen), plasma (sun, stars)

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Sample Problem #1

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Sample Problem #1

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Types of Mass

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Inertial Mass – an objects resistance to being accelerated by a force

The more inertial mass, the harder it is to accelerate the object of interest

Gravitational Mass – the amount of gravitational force experienced by an object

The more gravitational mass, the more gravitational force

Both types of mass are generally equal for practical purposes

Energy

Energy – often defined as the ability to do work or make a change in something

What is Work?

Work – the process or capacity to move an object

Both definitions are vague, because energy is often difficult to define

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Mass-Energy Equivalence

Scientists around the turn of the century proposed a strong relationship between matter and energy

1905 Albert Einstein formulated E=mc2, which show matter and energy are really one in the same

Led the way to nuclear energy, nuclear weapons, particle colliders, etc.

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Galileo - 1609

developed a systematic method of observing, experimenting, and analyzing…the scientific method

B. no set method – but scientists started to systematically analyze problems, along with keeping detailed records

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