[Physics Tips] Watch the signs

student,

Welcome to another issue of Physics Tips Daily - the free eZine to provide tips and tricks for students to survive and excel in physics.

Today's topic is the signs. The signs matter a greal deal in physics. Just think vectors!

A positive or a negative sign can make all the difference in a problem. Just as you made graphs or plot on axes in math class, you can use signs to establish direction in physics. In math, + on the y axis is arbitrarily assigned as up. - on the y axis is down. The same idea applies in physics.

The acceleration due to gravity is -9.8 m/s². Without saying anything else, this mean the acceleration is pointing downwards. This assumes we have setup the convention that up is positive. The negative sign doesn't mean its moving slower than zero, it simply refers to a direction.

If a ball is moving at +25 m/s, that means its traveling in whatever has been established as the positive direction. A velocity of -25 m/s means its traveling in the negative direction. They would both have the same speedometer reading, just different directions.

Tip of the Day: With any physics quantity, think of the signs and units too.

That should do it for today.

Keep it up with your study. "See" you tomorrow.

Meanwhile, Seize the Day!
Wayne Huang, PhD
http://www.RapidLearningCenter.com

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>> Physics Mastery = Core-Concepts + Problem-Solving + Super Review.
There you have it! It's that simple - just identify and understand the core concepts and their inter-connections, then apply the understanding to problem solving and finally super study the cheat sheets. You will be able to walk in to ace that exam with total confidence. Watch this movie and learn about this secret formula: http://www.rapidlearningcenter.com/TheMovie.html

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