Physics I Workbook For Dummies with Online Practice

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Published: January 6, 2022

Overview

Nail your next physics exam and prepare yourself for the next level of physics education

Physics isn’t the easiest part of high school, but it doesn’t have to be pull-your-hair-out hard. In Physics I Workbook For Dummies, you get practical guidance to reinforce what you already know and master new physics concepts. You’ll gain confidence in critical subject areas like motion, thermodynamics, and electromagnetism while setting yourself up for success in college- and university-level physics courses.

This book offers hands-on practice exercises in the book and on an online test bank that come with plain-English answers and step-by-step explanations so you can see what you did right and where you need practice. The perfect combination of instruction and application, Physics I Workbook For Dummies also provides:

• Understandable explanations of central physics concepts and the techniques you need to solve common problems
• Practice questions with complete answer explanations to test your knowledge as you progress
• Highlights of the ten most common pitfalls and traps that students encounter in physics assignments and exams and how to avoid them
• A collection of the ten most useful online physics resources, along with free, 1-year access to online chapter quizzes

Whether you’re planning to tackle the MCAT one day or just want to improve your performance on your next physics test, Physics I Workbook For Dummies offers you an opportunity to master a rewarding and challenging subject that unlocks countless educational and career opportunities.

Physics I Workbook For Dummies Cheat Sheet

Avoid difficulties when working on physics by knowing the common issues that can cause trouble in physics problems, understanding physical constants, and grasping principal physics equations.

Articles From The Book

61 results

Physics Articles

How to Find a Vector’s Magnitude and Direction

In physics, when you’re given the vector components, such as (3, 4), you can easily convert to the magnitude/angle way of expressing vectors using trigonometry. For example, take a look at the vector in the image. Suppose that you’re given the coordinates of the end of the vector and want to find its magnitude, v, and angle, theta. Because of your knowledge of trigonometry, you know Where tan theta is the tangent of the angle. This means that

theta = tan–1(y/x)
Suppose that the coordinates of the vector are (3, 4). You can find the angle theta as the tan–1(4/3) = 53 degrees. You can use the Pythagorean theorem to find the hypotenuse — the magnitude, v — of the triangle formed by x, y, and v: Plug in the numbers for this example to get So if you have a vector given by the coordinates (3, 4), its magnitude is 5, and its angle is 53 degrees.

Sample question

1. Convert the vector given by the coordinates (1.0, 5.0) into magnitude/angle format.

The correct answer is magnitude 5.1, angle 79 degrees.

1. Apply the Pythagorean theorem to find the magnitude. Plug in the numbers to get 5.1.

2. Apply the equation theta= tan–1(y/x) to find the angle. Plug in the numbers to get tan–1(5.0/1.0) = 79 degrees.

Practice questions

1. Convert the vector (5.0, 7.0) into magnitude/angle form.

2. Convert the vector (13.0, 13.0) into magnitude/angle form.

3. Convert the vector (–1.0, 1.0) into magnitude/angle form.

4. Convert the vector (–5.0, –7.0) into magnitude/angle form.

Following are answers to the practice questions:
1. Magnitude 8.6, angle 54 degrees

1. Apply the equation

to find the magnitude, which is 8.6.

1. Apply the equation theta = tan–1(y/x) to find the angle: tan–1(7.0/5.0) = 54 degrees.

2. Magnitude 18.4, angle 45 degrees

1. Apply the equation

to find the magnitude, which is 18.4.

1. Apply the equation theta = tan–1(y/x) to find the angle: tan–1(13.0/13.0) = 45 degrees.

3. Magnitude 1.4, angle 135 degrees

1. Apply the equation

to find the magnitude, which is 1.4.

2. Apply the equation theta = tan–1(y/x) to find the angle: tan–1(1.0/–1.0) = –45 degrees.

However, note that the angle must really be between 90 degrees and 180 degrees because the first vector component is negative and the second is positive. That means you should add 180 degrees to –45 degrees, giving you 135 degrees (the tangent of 135 degrees is also 1.0/–1.0 = –1.0).

4. Magnitude 8.6, angle 234 degrees

1. Apply the equation

to find the magnitude, which is 8.6.

2. Apply the equation theta = tan–1(y/x) to find the angle: tan–1(–7.0/–5.0) = 54 degrees.

However, note that the angle must really be between 180 degrees and 270 degrees because both vector components are negative. That means you should add 180 degrees to 54 degrees, giving you 234 degrees (the tangent of 234 degrees is also –7.0/–5.0 = 7.0/5.0).

Physics Articles

Important Physics Equations to Remember

Physics is packed with formulas and equations. This comprehensive list, arranged by topic, represents essential physics equations you need to keep handy when you're dealing with physics formulas.

Physics Articles

Physics: Transforming Energy between Mechanical and Thermal Forms

Thermodynamics is the study of how thermal energy (heat energy) and mechanical energy are related. It's an important topic in physics as well as in engineering. Engineers must employ thermodynamic principles whenever heat is involved. This includes the design of refrigerators, air conditioning units, automobiles, jet engines, and even computers.

One of the most important ideas within this topic is the first law of thermodynamics, which is a restatement of the law of conservation of energy, with an emphasis on the idea that mechanical energy and thermal energy can, indeed, be transformed into each other. It states that the change in energy of a gas is equal to the amount the gas is heated plus the amount of work that is done on that gas.

That's a mouthful, so the first law of thermodynamics is usually expressed as an equation:

U = Q + W

In this equation, ∆U is the change in internal energy of the gas (not including, for example, the energy due to the motion of the box containing the gas) and for an ideal gas is proportional to the change in temperature of the gas. Q is the amount the gas is heated, and W is the amount of work done on the gas. If the gas heats its surroundings (instead of the surroundings heating the gas), then Q is negative. Likewise, if the gas does work on its surroundings, then W is negative.

Here's a conceptual example: Imagine a balloon filled with helium. What happens to the balloon's temperature if you squeeze it? When you squeeze a balloon, you apply forces to that balloon's surface through a distance. In other words, you do work on the balloon. From the first law of thermodynamics, this means that you increase the internal energy, and thus the temperature, inside the balloon. The balloon's temperature then decreases again as the balloon heats its surroundings (a result of the second law of thermodynamics).

This example may seem trivial, but if you understand it, you're well on your way to understanding the first law of thermodynamics, as well as thermodynamics in general. In addition, this example is similar to what you find in everyday technology. Both refrigerators and air conditioning units contain compressors that act much as the balloon described.