Head First Physics

Advance Praise for Head First Physics; Praise for other Head First academic titles; Praise for the Head First Approach; ; Author of Head First Physics; How to Use this Book: Intro; Who is this book for?; We know what you're thinking; We know what your brain is thinking; Metacognition: thinking about thinking; Here's what WE did:; Here's what YOU can do to bend your brain into submission; Read Me; The technical review team; Acknowledgments; Safari® Books Online; Chapter 1: Think Like a Physicist: In the beginning ...; 1.1 Physics is the world around you; 1.2 You can get a feel for what's happening by being a part of it; 1.3 Use your intuition to look for 'special points'; 1.4 The center of the earth is a special point; 1.5 Ask yourself "What am I ALREADY doing as I reach the special point?"; 1.6 Where you're at - and what happens next?; 1.7 Now put it all together; 1.8 Your Physics Toolbox; Chapter 2: Making it all MEAN Something: Units and measurements; 2.1 It's the best music player ever, and you're part of the team!; 2.2 So you get on with measuring the myPod case; 2.3 When the myPod case comes back from the factory...; 2.4 ...it's waaay too big!; 2.5 There aren't any UNITS on the blueprint; 2.6 You'll use SI units in this book (and in your class); 2.7 You use conversion factors to change units; 2.8 You can write a conversion factor as a fraction; 2.9 Now you can use the conversion factor to update the blueprint; 2.10 You just converted the units for the entire blueprint!; 2.11 But there's STILL a problem ...; 2.12 What to do with numbers that have waaaay too many digits to be usable; 2.13 How many digits of your measurements look significant?; 2.14 Generally, you should round your answers to three significant digits; 2.15 Is it OK to round the myPod blueprint to three significant digits?; 2.16 You ALREADY intuitively rounded your original myPod measurements!; 2.17 Any measurement you make has an error (or uncertainty) associated with it; 2.18 The error on your original measurements should propagate through to your converted blueprint; 2.19 Right! Time to attack the blueprint again!; 2.20 STOP!! Before you hit send, do your answers SUCK?!; 2.21 You nailed it!; 2.22 When you write down a measurement, you need the right number of significant digits; 2.23 Your Physics Toolbox; Chapter 3: Scientific Notation, Area, and Volume: All numbers great and small; 3.1 A messy college dorm room; 3.2 So how long before things go really bad?; 3.3 Power notation helps you multiply by the same number over and over; 3.4 Your calculator displays big numbers using scientific notation; 3.5 Scientific notation uses powers of 10 to write down long numbers; 3.6 Scientific notation helps you with small numbers as well; 3.7 You'll often need to work with area or volume; 3.8 Look up facts in a book (or table of information); 3.9 Prefixes help with numbers outside your comfort zone; 3.10 Scientific notation helps you to do calculations with large and small numbers; 3.11 The guys have it all worked out; 3.12 200,000,000 meters cubed bugs after only 16 hours is totally the wrong size of answer!; 3.13 Be careful converting units of area or volume; 3.14 So the bugs won't take over ... unless the guys sleep in!; 3.15 Question Clinic: The "Converting units of area or volume" Question; 3.16 Your Physics Toolbox; Chapter 4: Equations and Graphs: Learning the lingo; 4.1 The new version of the Break Neck Pizza website is nearly ready to go live ...; 4.2 ...but you need to work out how to give the customer their delivery time; 4.3 If you write the delivery time as an equation, you can see what's going on; 4.4 Use variables to keep your equation general; 4.5 You need to work out Alex's cycling time; 4.6 When you design an experiment, think about what might go wrong!; 4.7 OK - time to recap where you're at...; 4.8 Conduct an experiment to find out Alex's speed; 4.9 Write down your results... in a table; 4.10 Use the table of distances and times to work out Alex's speed; 4.11 Random errors mean that results will be spread out; 4.12 A graph is the best way of taking an average of ALL your results; 4.13 Use a graph to show Alex's time for ANY distance; 4.14 The line on the graph is your best estimate for how long Alex takes to cycle ANY distance; 4.15 You can see Alex's speed from the steepness of the distance-time graph; 4.16 Alex's speed is the slope of the distance-time graph; 4.17 Now work out Alex's average speed from your graph; 4.18 You need an equation for Alex's time to give to the web guys; 4.19 Rearrange the equation to say "¿ time = something"; 4.20 Use your equation to work out the time it takes Alex to reach each house; 4.21 So you do a test run with the website ...; 4.22 So just convert the units, and you're all set...right?; 4.23 Include the cooking time in your equation; 4.24 The Break Neck website goes live, and the customers love it!; 4.25 A few weeks later, you hear from Break Neck again; 4.26 A graph lets you see the difference the stop lights made; 4.27 The stop lights change Alex's average speed; 4.28 Add on two minutes per stop light to give the customer a maximum delivery time ...; 4.29 ...the customers are extremely happy ...; 4.30 ...and you're invited to the Pizza Party; 4.31 Question Clinic: The "Did you do what they asked you" Question; 4.32 Your Physics Toolbox; Chapter 5: Dealing with Directions: Vectors; 5.1 The treasure hunt; 5.2 Displacement is different from distance; 5.3 Distance is a scalar; displacement is a vector; 5.4 You can represent vectors using arrows; 5.5 You found the next clue...; 5.6 You can add vectors in any order; 5.7 Well done - you've found the third clue!; 5.8 Question Clinic: The "Wheat from the chaff" Question; 5.9 Angles measure rotations; 5.10 Now you can get on with clue 3!; 5.11 If you can't deal with something big, break it down into smaller parts; 5.12 You move onto the fourth clue...; 5.13 Velocity is the 'vector version' of speed; 5.14 Write units using shorthand; 5.15 So, on to clue 4 ...; 5.16 You need to allow for the stream's velocity too!; 5.17 If you can find the stream's velocity, you can figure out the velocity for the boat; 5.18 It takes the boat time to accelerate from a standing start; 5.19 How do you deal with acceleration?; 5.20 So it's back to the boat ...; 5.21 Vector, Angle, Velocity, Acceleration = WINNER!!!; 5.22 Your Physics Toolbox; 5.23 Question Clinic: The "Design an experiment" Question; Chapter 6: Displacement, Velocity, and Acceleration: What's going on?; 6.1 Just another day in the desert ...; 6.2 ...and another Dingo-Emu moment!; 6.3 How can you use what you know?; 6.4 The cage accelerates as it falls; 6.5 ' Vectorize' your equation; 6.6 You want an instantaneous velocity, not an average velocity; 6.7 You already know how to calculate the slope of a straight line...; 6.8 A point on a curved line has the same slope as its tangent; 6.9 The slope of something's velocity-time graph lets you work out its acceleration; 6.10 Work out the units of acceleration; 6.11 Success! You worked out the velocity after 2.0 s - and the cage won't break!; 6.12 Now onto solve for the displacement!; 6.13 Your Physics Toolbox; Chapter 7: Equations of motion (part 1): Playing With Equations; 7.1 How high should the crane be?; 7.2 Graphs and equations both represent the real world; 7.3 You're interested in the start and end points; 7.4 You have an equation for the velocity - but what about the displacement?; 7.5 See the average velocity on your velocity-time graph; 7.6 Test your equations by imagining them with different numbers; 7.7 Calculate the cage's displacement!; 7.8 You know how high the crane should be!; 7.9 But now the Dingo needs something more general; 7.10 A substitution will help; 7.11 Get rid of the variables you don't want by making substitutions; 7.12 Continue making substitutions ...; 7.13 You did it - you derived a useful equation for the cage's displacement!; 7.14 Check your equation using Units; 7.15 Check your equation by trying out some extreme values; 7.16 Your equation checks out!; 7.17 Question Clinic: The "Substitution" Question; 7.18 Question Clinic: The "Units" or "Dimensional analysis" Question; 7.19 Think like a physicist!; 7.20 Your Physics Toolbox; Chapter 8: Equations of Motion (Part 2): Up, up, and... back down; 8.1 Previously ...; 8.2 Now ACME has an amazing new cage launcher; 8.3 The acceleration due to gravity is constant; 8.4 Velocity and acceleration are in opposite directions, so they have opposite signs; 8.5 You can use one graph to work out the shapes of the others; 8.6 Is a graph of your equation the same shape as the graph you sketched?; 8.7 Ready to launch the cage!; 8.8 Fortunately, ACME has a rocket-powered hovercraft!; 8.9 You can work out a new equation by making a substitution for t; 8.10 Multiply out the parentheses in your equation; 8.11 You have two sets of parentheses multiplied together; 8.12 Where you're at with your new equation; 8.13 You need to simplify your equation by grouping the terms; 8.14 You can use your new equation to work out the stopping distance; 8.15 There are THREE key equations you can use when there's constant acceleration; 8.16 You need to work out the launch velocity that gets the Dingo out of the Grand Canyon!; 8.17 The launch velocity's right!; 8.18 You need to find another way of doing this problem; 8.19 Question Clinic: The "Sketch a graph" or "Match a graph" Question; 8.20 Question Clinic: The "Symmetry" and "Special points" Questions; 8.21 Your Physics Toolbox; Chapter 9: Triangles, Trig and Trajectories: Going two-dimensional; 9.1 Camelot - we have a problem!; 9.2 How wide should you make the moat?; 9.3 Looks like a triangle, yeah?; 9.4 A scale drawing can solve problems; 9.5 Pythagoras' Theorem lets you figure out the sides quickly; 9.6 Sketch + shape + equation = Problem solved!; 9.7 You kept them out!; 9.8 But the attackers get smarter!; 9.9 Camelot ... we have ANOTHER problem!; 9.10 Relate your angle to an angle inside the triangle; 9.11 Classify similar triangles by the ratios of their side lengths; 9.12 Sine, cosine and tangent connect the sides and angles of a right-angled triangle; 9.13 How to remember which ratio is which??; 9.14 Calculators have sin(¿), cos(¿) and tan(¿) tables built in; 9.15 Back at the castle, everyone's depending on you!; 9.16 You can know everything! *; 9.17 Does your answer SUCK?; 9.18 Uh oh. Gravity...; 9.19 The cannonball's velocity and acceleration vectors point in different directions; 9.20 Gravity accelerates everything downwards at 9.8 m/s2; 9.21 The horizontal component of the velocity can't change once you've let go; 9.22 The horizontal component of a projectile's velocity is constant; 9.23 The same method solves both problems; 9.24 Question Clinic: The "Projectile" Question; 9.25 And so they ran away ...; 9.26 Question Clinic: The "Missing steps" Question; 9.27 Your Physics Toolbox; Chapter 10: Momentum Conservation: What Newton Did; 10.1 The pirates be havin' a spot o' bother with a ghost ship ...; 10.2 What does the maximum range depend on?; 10.3 Firing at 45° maximizes your range; 10.4 You can't do everything that's theoretically possible - you need to be practical too; 10.5 Sieges-R-Us has a new stone cannonball, which they claim will increase the range!; 10.6 Massive things are more difficult to start off; 10.7 Massive things are more difficult to stop; 10.8 Newton's First Law; 10.9 Mass matters; 10.10 A stone cannonball has a smaller mass - so it has a larger velocity. But how much larger?; 10.11 Here's your lab equipment; 10.12 How are force, mass and velocity related?; 10.13 Vary only one thing at a time in your experiment; 10.14 Mass x velocity - momentum - is conserved; 10.15 A greater force acting over the same amount of time gives a greater change in momentum; 10.16 Write momentum conservation as an equation; 10.17 Momentum conservation and Newton's Third Law are equivalent; 10.18 You've calculated the stone cannonball's velocity...; 10.19 ...but you want the new range!; 10.20 Use proportion to work out the new range; 10.21 You solved the pirates' problem!; 10.22 Question Clinic: The "Proportion" Question (often multiple choice); 10.23 Your Physics Toolbox; Chapter 11: Weight and the normal force: Forces for courses; 11.1 WeightBotchers are at it again!; 11.2 Is it really possible to lose weight instantly?!; 11.3 Scales work by compressing or stretching a spring; 11.4 Mass is a measurement of "stuff"; 11.5 Weight is a force; 11.6 The relationship between force and mass involves momentum; 11.7 If the object's mass is constant, Fnet = ma; 11.8 The scales measure the support force; 11.9 Now you can debunk the machine!; 11.10 The machine reduces the support force; 11.11 Force pairs help you check your work; 11.12 You debunked WeightBotchers!; 11.13 But WeightBotchers are back!; 11.14 A surface can only exert a force perpendicular (or normal) to it; 11.15 When you slide downhill, there's zero perpendicular acceleration; 11.16 Use parallel and perpendicular force components to deal with a slope; 11.17 Another fake busted!; 11.18 Question Clinic: The "Free body diagram" Question; 11.19 Question Clinic: The "Free body diagram" Question; 11.20 Your Physics Toolbox; Chapter 12: Using forces, momentum, friction and impulse: Getting on with it; 12.1 It's ... SimFootball!; 12.2 Momentum is conserved in a collision; 12.3 But the collision might be at an angle; 12.4 A triangle with no right angles is awkward; 12.5 Use component vectors to create some right-angled triangles; 12.6 The programmer includes 2D momentum conservation ...; 12.7 ...but the players keep on sliding for ever!; 12.8 In real life, the force of friction is present; 12.9 Friction depends on the types of surfaces that are interacting; 12.10 Friction depends on the normal force; 12.11 Be careful when you calculate the normal force; 12.12 You're ready to use friction in the game!; 12.13 Including friction stops the players from sliding forever!; 12.14 The sliding players are fine - but the tire drag is causing problems; 12.15 Using components for the tire drag works!; 12.16 Question Clinic: The "Friction" Question; 12.17 How does kicking a football work?; 12.18 F¿t is called impulse; 12.19 The game's great - but there's just been a spec change!; 12.20 The strength of the moon's gravitational field is lower then the Earth's; 12.21 For added realism, sometimes the players should slip; 12.22 You can change only direction horizontally on a flat surface because of friction; 12.23 The game is brilliant, and going to X-Force rocks!; 12.24 Newton's Laws give you awesome powers; 12.25 Your Physics Toolbox; Chapter 13: Torque and Work: Getting a lift; 13.1 Half the kingdom to anyone who can lift the sword in the stone ...; 13.2 Can physics help you to lift a heavy object?; 13.3 Use a lever to turn a small force into a larger force; 13.4 Do an experiment to determine where to position the fulcrum; 13.5 Zero net torque causes the lever to balance; 13.6 Use torque to lift the sword and the stone!; 13.7 Question Clinic: The "Two equations, two unknowns" Question; 13.8 So you lift the sword and stone with the lever ...; 13.9 ...but they don't go high enough!; 13.10 You can't get something for nothing; 13.11 When you move an object against a force, you're doing work; 13.12 The work you need to do a job = force x displacement; 13.13 Which method involves the least amount of work?; 13.14 Work has units of Joules; 13.15 Energy is the capacity that something has to do work; 13.16 Lifting stones is like transferring energy from one store to another; 13.17 Energy conservation helps you to solve problems with differences in height; 13.18 One of our stackable stones is missing ...; 13.19 Will energy conservation save the day?; 13.20 You need to do work against friction as well as against gravity; 13.21 Doing work against friction increases internal energy; 13.22 Heating increases internal energy; 13.23 It's impossible to be 100% efficient; 13.24 Your Physics Toolbox; Chapter 14: Energy Conservation: Making your life easier; 14.1 The ultimate bobsled experience; 14.2 Forces and component vectors solve the first part ...; 14.3 ...but the second part doesn't have a uniform slope; 14.4 A moving object has kinetic energy; 14.5 The kinetic energy is related to the velocity; 14.6 Calculate the velocity using energy conservation and the change in height; 14.7 You've used energy conservation to solve the second part; 14.8 In the third part, you have to apply a force to stop a moving object; 14.9 Putting on the brake does work on the track; 14.10 Doing work against friction increases the internal energy; 14.11 Energy conservation helps you to do complicated problems in a simpler way; 14.12 There's a practical difference between momentum and kinetic energy; 14.13 Question Clinic: The "Show that" Question; 14.14 Question Clinic: The "Energy transfer" Question; 14.15 After the roaring success of SimFootball, it's time for SimPool; 14.16 Momentum conservation will solve an inelastic collision problem; 14.17 You need a second equation for an elastic collision; 14.18 Energy conservation gives you the second equation that you need!; 14.19 Factoring involves putting in parentheses; 14.20 You can deal with elastic collisions now; 14.21 In an elastic collision, the relative velocity reverses; 14.22 The pool ball collisions work!; 14.23 There's a gravity-defying trick shot to sort out ...; 14.24 Where is the problem with the programmer's reasoning?; 14.25 The initial collision is inelastic - so mechanical energy isn't conserved; 14.26 Use momentum conservation for the inelastic part; 14.27 Question Clinic: The "Ballistic pendulum" Question; 14.28 Your Physics Toolbox; Chapter 15: Tension, Pulleys and Problem Solving: Changing direction; 15.1 It's a bird... it's plane...; 15.2 ...no, it's... a guy on a skateboard?!; 15.3 Always look for something familiar; 15.4 Michael and the stack accelerate at the same rate; 15.5 Use tension to tackle the problem; 15.6 Look at the big picture as well as the parts; 15.7 But the day before the competition ...; 15.8 Using energy conservation is simpler than using forces; 15.9 There goes that skateboard...; 15.10 Your Physics Toolbox; Chapter 16: Circular Motion (Part 1): From a to ¿; 16.1 Limber up for the Kentucky Hamster Derby; 16.2 You can revolutionize the hamsters' training; 16.3 Thinking through different approaches helps; 16.4 A circle's radius and circumference are linked by ¿; 16.5 Convert from linear distance to revolutions; 16.6 Convert the linear speeds into Hertz; 16.7 So you set up the machine ...; 16.8 ...but the wheel turns too slowly!; 16.9 Try some numbers to work out how things relate to each other; 16.10 The units on the motor are radians per second; 16.11 Convert frequency to angular frequency; 16.12 The hamster trainer is complete!; 16.13 A couple of weeks later ...; 16.14 You can increase the (linear) speed by increasing the wheel's radius; 16.15 Question Clinic: The "Angular quantities" Question; 16.16 Your Physics Toolbox; Chapter 17: Circular Motion (Part 2) Staying on track; 17.1 Houston ... we have a problem; 17.2 When you're in freefall, objects appear to float beside you; 17.3 What's the astronaut missing, compared to when he's on Earth?; 17.4 Can you mimic the contact force you feel on Earth?; 17.5 Accelerating the space station allows you to experience a contact force; 17.6 You can only go in a circle because of a centripetal force; 17.7 Centripetal force acts towards the center of the circle; 17.8 The astronaut experiences a contact force when you rotate the space station; 17.9 What affects the size of centripetal force?; 17.10 Spot the equation for the centripetal acceleration; 17.11 Give the astronauts a centripetal force; 17.12 The astronauts want as much floor space as possible; 17.13 Here, the floor space is the area of a cylinder's curved surface; 17.14 If you work out the volume, you can calculate the astronauts' floor space; 17.15 Let's test the space station...; 17.16 Fewer uncomfortable things happen with the 100 m radius space station; 17.17 You've sorted out the space station design!; 17.18 Question Clinic: The "Centripetal force" Question; 17.19 Back to the track!; 17.20 The bobsled needs to turn a corner; 17.21 Angling the track gives the normal force a horizontal component; 17.22 When you slide downhill, there's no perpendicular acceleration; 17.23 When you turn a corner, there's no vertical acceleration; 17.24 How to deal with an object on a slope; 17.25 Banking the track works ...; 17.26 ...but now they want it to loop-the-loop!; 17.27 The "support force" (normal force or tension force) required for a vertical circle varies; 17.28 Any force that acts towards the center of the circle can provide a centripetal force; 17.29 How fast does the bobsled need to go?; 17.30 Question Clinic: The "Banked curve" Question; 17.31 Question Clinic: The "Vertical circle" Question; 17.32 Your Physics Toolbox; Chapter 18: Gravitation and Orbits: Getting away from it all; 18.1 Party planners, a big event, and lots of cheese; 18.2 What length should the cocktail sticks be?; 18.3 The cheese globe is a sphere; 18.4 The surface area of the sphere is the same as the surface area of the cheese; 18.5 Let there be cheese...; 18.6 ...but there are gaps in the globe!; 18.7 The party's on!; 18.8 To infinity - and beyond!; 18.9 Earth's gravitational force on you becomes weaker as you go further away; 18.10 Gravitation is an inverse square law; 18.11 Now you can calculate the force on the spaceship at any distance from the Earth; 18.12 The potential energy is the area under the force-displacement graph; 18.13 If U = 0 at infinity, the equation works for any star or planet; 18.14 Use energy conservation to calculate the astronaut's escape velocity; 18.15 We need to keep up with our astronaut; 18.16 The centripetal force is provided by gravity; 18.17 With the comms satellites in place, it's Pluto (and beyond); 18.18 Question Clinic: The "gravitational force = centripetal force" Question; 18.19 Your Physics Toolbox; Chapter 19: Oscillations (Part 1): Round and round; 19.1 Welcome to the fair!; 19.2 Reproduce the duck on the display; 19.3 The screen for the game is TWO-DIMENSIONAL; 19.4 So we know what the duck does...; 19.5 ...but where exactly is the duck?; 19.6 Any time you're dealing with a component vector, try to spot a right-angled triangle; 19.7 Let's show Jane the display; 19.8 The second player sees the x-component of the duck's displacement; 19.9 We need a wider definition of cosine, too; 19.10 sine and cosine are related to each other; 19.11 Let the games begin!; 19.12 Jane's got another request: What's the duck's velocity from each player's point of view?; 19.13 Get the shape of the velocity-time graph from the slope of the displacement-time graph; 19.14 The game is complete!; 19.15 Your Physics Toolbox; Chapter 20: Oscillations (Part 2): Springs 'n' swings; 20.1 Get rocking, not talking; 20.2 The plant rocker needs to work for three different masses of plant; 20.3 A spring will produce regular oscillations; 20.4 Displacement from equilibrium and strength of spring affect the force; 20.5 A mass on a spring moves like a side-on view of circular motion; 20.6 A mass on a spring moves with simple harmonic motion; 20.7 Simple harmonic motion is sinusoidal; 20.8 Work out constants by comparing a situation-specific equation with a standard equation; 20.9 Question Clinic: The "This equation is like that one" Question; 20.10 You rock! Or at least Anne's plants do; 20.11 But Anne forgot to mention someting ...; 20.12 The plants rock - and you rule!; 20.13 But now the plant rocker's frequency has changed ...; 20.14 The frequency of a horizontal spring depends on the mass; 20.15 Will using a vertical spring make a difference?; 20.16 A pendulum swings with simple harmonic motion; 20.17 What does the frequency of a pendulum depend on?; 20.18 The pendulum design works!; 20.19 Question Clinic: The "Vertical spring" Question; 20.20 Question Clinic: The "How does this depend on that" Question; 20.21 Your Physics Toolbox; Chapter 21: Think Like a Physicist: It's the final chapter; 21.1 You've come a long way!; 21.2 Now you can finish off the globe; 21.3 The round-trip looks like simple harmonic motion; 21.4 But what time does the round-trip take?; 21.5 You can treat the Earth like a sphere and a shell; 21.6 The net force from the shell is zero; 21.7 The force is proportional to the displacement, so your trip is SHM; 21.8 Question Clinic: The "Equation you've never seen before" Question; 21.9 You know your average speed - but what's your top speed?; 21.10 Circular motion from side on looks like simple harmonic motion; 21.11 You can do (just about) anything!; Leftovers: The top 6 things (that we didn't cover before, but are covering now); #1 Equation of a straight line graph, y = mx + c; #2 Displacement is the area under the velocity-time graph; #3 Torque on a bridge; #4 Power; #5 Lots of practice questions; #6 Exam tips; Equation Table: Point of Reference; Mechanics equation table;