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Basics of gravity and the Law of Universal Gravitation.

The beauty of a coral reef, the warm radiance of sunshine, the sting of sunburn, the X-ray revealing a broken bone, even microwave popcorn—all are brought to us by electromagnetic waves. The list of the various types of electromagnetic waves, ranging from radio transmission waves to nuclear gamma-ray (γ-ray) emissions, is interesting in itself.

Even more intriguing is that all of these different phenomena are manifestations of the same thing—electromagnetic waves (see Figure 15.1). What are electromagnetic waves? How are they created, and how do they travel? How can we understand their widely varying properties? What is the relationship between electric and magnetic effects? These and other questions will be explored.

An image that illustrates light reflecting off a plain mirror.

This unit is about how things move along a straight line or, more scientifically, how things move in one dimension. Examples of this would be the movement (motion) of cars along a straight road or of trains along straight railway tracks.

In this lesson you will learn:

• to distinguish between distance and displacement
• to distinguish between speed and velocity
• understand acceleration
• interpret time-velocity graphs
• use equations of uniformly accelerated motion
• understand the concept of gravitational force

In this chapter, we’ll use vectors to expand our understanding of forces and motion into two dimensions. Most real-world physics problems (such as with the game of pool pictured here) are, after all, either two- or three-dimensional problems and physics is most useful when applied to real physical scenarios. We start by learning the practical skills of graphically adding and subtracting vectors (by using drawings) and analytically (with math). Once we’re able to work with two-dimensional vectors, we apply these skills to problems of projectile motion, inclined planes, and harmonic motion.

You want a projectile to fly as far as possible, at which angle should you launch it? We'll start with formulas for the initial velocity.

Photoelectric materials emit electrons when they absorb light of a high-enough frequency.

Plotting projectile displacement, acceleration, and velocity as a function of time.

Figuring out the horizontal displacement for a projectile launched at an angle.