Welcome back to Jeopardy! Please raise your hand to answer.

1. Welcome back to Jeopardy! • Please raise your hand to answer. • An answer must be in the form of a question. • Each correct answer is worth five extra credit points. • The maximum daily score is 25 points. • Each incorrect answer costs five extra credit points. • All negative scores will be cancelled at the end of the game (today).

2. Units are distance divided by time. • What is speed? • This may be calculated as total distance covered divided by the time interval. • What is average speed? • This is always average speed multiplied by time interval. • What is total distance traveled? • This has speed and direction. • What is velocity?

3. Units are velocity divided by time. • What is acceleration? • Motion with a constant downward acceleration of 9.8 m/s2. • What is free fall? • Speed at an instant vs. total distance divided by total time. • What is the difference between instantaneous speed and average speed?

4. Velocity describes both speed and direction. • What is the difference between speed and velocity? • V = at • What is the equation for the speed of an object after time t, starting from rest, due to constant acceleration a? • d = 0.5at2 • What is the equation for the distance an object travels during time t, starting from rest, due to constant acceleration a?

5. V = V0 + at. • What is the equation for velocity of an object after time t, starting with speed V0, due to constant acceleration a? • d = V0 t + 0.5at2. • What is the equation for the distance an object travels during time t, starting with initial velocity V0, due to constant acceleration a?

6. In this type of motion, horizontal and vertical components are independent. • What is projectile motion? • First, vertical and horizontal lines are drawn from the tail of the vector. Second, a rectangle is drawn that encloses the vector as its diagonal. • What is vector resolution? • The horizontal velocity is zero, but the vertical velocity decreases 9.8 m/s2. • What is free fall?

7. It has four sides, with opposite sides parallel to each other. • What is a parallelogram? • To find this kind of sum, you need to construct a parallelogram. The sum or resultant is the diagonal. • What is a vector sum? • Satellites in low circular orbit have this speed. • What is 8 km/s?

8. This type of triangle has angles of 37o, 53o and 90o. • What is a 3,4,5 triangle? • In the absence of this, all objects fall with the same acceleration. • What is air resistance? • A projectile must move this fast so that the curve it follows matches the curve of Earth. • What is 8 km/s? • Only this force acts on a high satellite. • What is gravity?

9. He stated that if friction were entirely absent, a ball rolling horizontally would move forever. • Who was Galileo? • This scientist was born in the year Galileo died. • Who was Isaac Newton? • Every object continues in a state of rest, or of motion in a straight line at constant speed, unless it is compelled to change that state by forces acting upon it.

10. What is Newton’s first law, usually called the law of inertia? • The planets would move in straight lines at constant speed. • What would happen if the force of gravity between the sun and planets suddenly disappeared? • An object has little of this if its motion is easily changed. • What is inertia?

11. This is the quantitative measure of inertia. Its unit is the kilogram. • What is mass? • Unlike mass, this quantity varies with height, but it is proportional to mass. • What is weight? • This formula connects weight W, mass m and gravitational acceleration g. • W = mg • Gravitational acceleration g is not constant. • Why does your weight vary with height?

12. Qualitatively, this is a push or a pull, in some direction. Its unit is the Newton (N). • What is a force? • This is the name given to the vector combination of all forces acting on an object. • What is the net force? • This is the condition when net force is zero. • What is equilibrium? • This force cancels your weight when you are motionless. • What is the support force exerted on you?

13. A person with a mass of 50 kg has approximately this much weight. • What is 500 N? • To lose weight without eating less. • Why go to the moon? • V = 6.28 R/T • What is the speed V of an object which moves around a circle of radius R in time T? • A = V2/R • What is the acceleration A of an object which moves around a circle with speed V?

14. The net force (including air resistance) is zero. • When is terminal speed attained? • a = Fnet/m • What is acceleration of an object according to Newton’s second law? • Change in velocity/time • What is acceleration? • P = F/A • What is pressure P due to force F on area A?

15. The acceleration produced by a net force on an object is directly proportional to the magnitude of the net force, is in the same direction as the net force, and is inversely proportional to the mass of the object. • What is Newton’s second law? • It is the mass of an object multiplied by its velocity. • What is the momentum of an object? • Friction or drag that acts on something moving through air.

16. What is air resistance? • Interaction between a baseball and a bat. • What is an example of action and reaction in the game of baseball? • The force of air resistance balances the force of gravity. • When is terminal speed attained? • The cause of acceleration. • What is net force?

17. ~ • What is the symbol for “directly proportional to”? • Pascal • What is the unit of pressure? • Kilogram divided by (meter times second2). • What is a pascal? • Resultant of all applied forces. • What is meant by the net force on an object?

18. Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object. • What is Newton’s third law? • The whirling blades are shaped to force air particles downward (action), and the air forces the blades upward (reaction). This upward reaction force is called lift. When lift equal weight of craft, it hovers in midair. • How does a helicopter get its lifting force?

19. It produces a pair of forces, action and reaction, equal in strength and opposite in direction. • What is an interaction between two objects? • It produces a pair of gravitational forces, action and reaction, equal in strength and opposite in direction. • What is a gravitational interaction between two objects?

20. It produces a pair of electrical forces, action and reaction, equal in strength and opposite in direction. • What is an electrical interaction between two objects? • It produces a pair of magnetic forces, action and reaction, equal in strength and opposite in direction. • What is a magnetic interaction between two objects?

21. It is mass times velocity or, in abbreviated notation, mv. • What is momentum? It is force times time interval or, in abbreviated notation, Ft. • What is impulse? • How is impulse related to momentum change?

22. In the absence of an external force, the momentum of a system remains unchanged. • What is the law of conservation of momentum? • Objects collide without being permanently deformed and without generating heat. • What is an elastic collision? • Colliding objects become tangled or couple together. • What is an inelastic collision?

23. Conservation of momentum and conservation of energy. • What are the two most powerful tools of mechanics? • The momentum before the collision is the same as the momentum after the collision. • What does it mean to say that momentum is conserved in a collision? • It is the quantity force times distance. • What is work?

24. The two things are (1) the application of a force, and (2) the movement of something by that force. • What two things enter into every case where work is done? • The unit of work. • What is a joule? • It is the rate of doing work. It’s unit is known as the watt. • What is power?

25. Kinetic and potential. • What are the two most common forms of mechanical energy? • PE = mgh. • How much potential energy does a mass m have from being lifted a distance h? • KE = 0.5mv2. • How much kinetic energy does a mass m have when its speed is v? • Energy cannot be created or destroyed. It can be transformed from one form to another, but the total amount of energy never changes.

26. What is the law of conservation of energy? • An object does this when it turns around an internal axis. • What is to rotate? • An object does this when it turns around an external axis. • What is to revolve? • An object moving in a circle with constant speed is acted on by this type of force. • What is a centripetal force?

27. This is a fictitious force with a name of its own. For an astronaut rotating in a space laboratory, it can simulate gravity. For a pilot or passenger in projectile motion, it can simulate weightlessness. • What is the centrifugal force? • To gain weight without eating more. • Why go to Jupiter? • This is why when we jump we don’t just keep floating in the air. • What is gravity?

28. This is approximately the acceleration due to gravity. • What is 10 m/s2? • Without this, a ball would roll forever on a horizontal surface. • What is friction? • This quantity has magnitude and direction. • What is a vector? • This quantity has only magnitude. • What is a scalar?

29. A ball rolling off of a table is an example of this. • What is a projectile? • This is a projectile traveling around Earth. • What is a satellite?

30. This property makes wood a good choice for handles on cooking utensils. • What is low heat conductivity? • This is the change of phase from liquid to gas. It takes place at the surface of the liquid. • What is evaporation? • This is a synonym for molecules in the gaseous phase. • What is vapor? • The three common phases of matter. • What are solid, liquid, and gas?

31. When this happens, the temperature on the Celsius scale is said to be 0o. • What is freezing or coexistence of ice and water? • When this happens, the temperature on the Celsius scale is said to be 100o. • What is boiling or coexistence of water and steam? • This produces the sensation of warmth that you feel when you touch a hot surface.

32. What is the transfer of kinetic energy by molecules in the surface to molecules in your fingers? • This is how heat is transferred through metal. • What is conduction? • These materials are the best conductors. • What are materials composed of atoms with “loose” outer electrons? • Heat is energy and is tangible. This is not. • What is cold, or the absence of heat?

33. The quantity that tells how hot or cold something is compared with a standard. • What is temperature? • Nearly all matter does this when temperature increases. • What is thermal expansion? • It shows thermal expansion and contraction of a liquid in a glass tube using a scale. • What is a thermometer?

34. These two properties determine the phase of a substance. • What are temperature and pressure? • In this form of heat transfer, energy moves from one place to another, but molecules do not. • What is conduction? • In this form of heat transfer, molecules of the hotter substance move from one place to another. • What is convection?

35. This property explains why, at a coastline, land warms faster during the day than water. • What is specific heat capacity? • This is the usual wind direction, at a coastline, during the day. • What is a sea breeze, from sea to land? • In the atmosphere, rising air experiences these. • What are expansion and cooling?

36. This is the opposite of evaporation. • What is condensation? • Rising moist air forms these, but rising dry air does not. • What are clouds? • This is basically a cloud that forms near the ground. • What is fog? • Objects in contact at the same temperature. • What is thermal equilibrium?

37. This is the amount of heat required to raise the temperature of one gram of water by one degree Celsius. • What is a calorie? • The units of this property are calories/gram/degree Celsius. • What is specific heat capacity? • All objects emit this in a mixture of wavelengths. • What is radiant energy?

38. Hot bodies emit primarily this kind of radiation. • What is short wavelength radiation? • Cold bodies emit primarily this kind of radiation. • What is long wavelength radiation? • This is the opposite of freezing. • What is melting? • Energy required for freezing or melting. • What is heat of fusion?

39. Energy required for vaporization or condensation. • What is heat of vaporization? • Heat of fusion for water. • What is 80 calories per gram? • Heat of vaporization for water. • What is 540 calories per gram? • Temperature at the bottom of Lake Tahoe. • What is 4o C?

40. Reason the temperature at the bottom of all deep lakes is 4o C. • At what temperature is the density of water greatest? • This adverb describes how boiling point depends on atmospheric pressure. • What is directly? • Best color for maximum radiation absorption. • What is black? • Rate of cooling ~ delta T.

42. This is the study of heat and its transformation into mechanical energy. • What is thermodynamics? • This used to be called “caloric” and flows from hot objects to cold objects. • What is heat? • In this kind of compression or expansion of a system, no heat enters or leaves the system. • What is an adiabatic change?

43. If a cold brick warmed a hot brick, this law would be violated. • What is the second law of thermodynamics? • This is an object which can give up heat or absorb it without change of temperature. • What is a heat reservoir? • This French engineer made a fundamental discovery about heat engines in 1824. • Who was Sadi Carnot?

44. In natural systems, order tends to disorder. • What is the second law of thermodynamics? • This is the measure of disorder. • What is entropy? • Heat added to a system equals the sum of increase in internal energy plus external work done by the system. • What is the first law of thermodynamics? • This is the lowest limit of temperature. • What is absolute zero, or -273o C?

45. By this, we mean any group of atoms, molecules, particles, or objects. • What is a system? • This type of automobile engine has no spark plugs. • What is a diesel engine? • This person invented the diesel engine. • Who was Rudolph Diesel? • Heat flows naturally only in this direction. • What is from hot to cold?

46. When work is done by a heat engine running between two temperatures Thot and Tcold, only some of the input heat at Thot can be converted to work, and the rest is expelled as heat at Tcold. • What is another form of the second law of thermodynamics, applied to heat engines? • This law of thermodynamics is a probability statement. • What is the second law of themodynamics?

47. At this temperature, no more energy can be extracted from a substance and no further lowering of its temperature is possible. • What is absolute zero, or 0 K? • Change in temperature is proportional to change in pressure. • What is the adiabatic form of the first law of thermodynamics? • Chinook winds. • What are westerly, warm, dry winds, at the eastern edge of the Rocky Mountains?

48. Cold, mountain-top air descends and is compressed adiabatically (warmed). • How are chinook winds formed? • Heat will never of itself flow from a cold object to hot object. What, never? Well, hardly ever. • What is the probability interpretation of the second law of thermodynamics? • This is basically a heat engine in reverse. • What is a refrigerator?

49. Of the three common units of temperature, Fahrenheit, Celsius, and Kelvin, these two are equal. • What are Celsius and Kelvin degrees? • Intake, compression, power, and exhaust. • What are the four strokes of an internal combustion engine? • Ten degrees C per kilometer. • How much does the temperature of dry air decrease with increasing altitude?

50. Ideal efficiency of a heat engine. • What is (T2 - T1)/T2? • Actual efficiency of a heat engine. • What is (Q2 - Q1)/Q2? • Physicist’s term for messiness. • What is disorder? • 273 K. • What is the freezing point of water? • 373 K. • What is the boiling point of water?