Phys 105 Exam 2

1)projectiles launched at 8km/s travel in circular path. What path will a projectile going greater than 8km/s follow? 2)what path of motion do planets follow 5)Satellite motion: How does total energy change at beginning of orbit vs toward end of orbit 6)The speed of a satellite in an elliptical orbit a)varies b)remains constant c)acts at right angles to its motion d)all of the above 7)in orbit: are PE and KE always the same? When is KE max?

1)Elliptical 2)elliptical 5)does not change---SUM of KE and PE are always the same (KE due to motion, PE due to position) 6)varies--half the time: recedes from Earth and loses speed; other half of time: approaches Earth and gains speed 7)NO; KE max when PE is minimum and vice versa *total energy is the same though at all times*

*Radiation part 2---Heat radiation= infrared radiation* 1)Radiant energy encountering an object leads to it being partly reflected and partly absorbed. Which part is felt as warmth? 2)are good emitters of radiant energy good absorbers or poor absorbers? 3)Does a good absorber reflect a lot or little radiant energy 4)Why doesn't pure snow melt rapidly under sunlight? 5)Is a hot pizza left in the cold outside a net emitter or net absorber of radiant energy? Does it become cooler or warmer? 6)^hot pizza in hotter oven

1)absorbed 2)good absorbers--it's why we never run out of radiant energy 3)little (black= absorber) 4)Pure snow (white) is a good reflector and therefore a poor absorber 5)net emitter (to cold air)---becomes cooler because it emitts more than it absorbs 6)net absorber--becomes warmer

1)true or false: atoms in a solid are still 2)What determines some properties of a solid and what are the 4 types of these

1)false--they vibrate about its own position (whether they are in a crystalline state or in an amorphous state) 2)electrical bonding---ionic, covalent, metallic, Vander Waals (weakest)

1)Is energy required or released when going from Solid to liquid? 2)^liquid to solid

1)required 2)released

1)What is angular momentum and its equation 2)correlation between rotational inertia and rotational speed---what concept is this 3)equation for angular momentum for an object that is small compared with the radial distance to its axis

1)the inertia of rotation---angular momentum= rotational inertia x angular velocity 2)as rotational inertia decreases, rotational speed increases---conservation of angular momentum 3)Angular momentum= mvr (mass times velocity times radius)

When a car drives off a cliff, why does it rotate forward as it falls?

With all 4 wheels on the ground, the CG is above its support base. When going off the cliff, the front wheels leave the ground so its support base shrinks to the part of the car that is not hanging over the cliff, causing the car's CG to extend beyond the support base and rotate forward

Explain how a thermos works (conduction, convection, vacuum, silver, radiation)

*Liquids in a vacuum will remain close to its original temperature for many hours* --Conduction through vacuum is impossible, and vacuum has no fluid to convect so there is not heat loss --the walls of the thermos are silvered, which is a good reflector and bad absorber, meaning heat will be reflected back into the bottle rather than absorbed by radiant energy from the outside

A boy standing on a 5 meter tower throws a ball 20m downrange. What is his pitching speed?

*Speed= distance/time* *d= 5(t^2)* ---d= meters falling d= 5 meters 5= 5(t^2) t=1 == speed= 20/1 speed= 20m/s

1)Although warm air rises, why are mountaintops cold and snow covered, while the valleys below are warm and green? a)warm air cools when rising b)there is a thick insulating blanket of air above valleys c)both A and B d)none of the above 2)What is the only form of heat transfer that can occur through a vacuum

1) C. Both A and B (B because atmosphere acts as a blanket that keeps valleys from freezing at night) 2)Radiation (i.e. radiant energy from Earth to vacuum of outer space)

1)Universal law of gravity---Everybody attracts every other body with a force that is _________ proportional to the product of their masses and _______ inversely proportional to the square of the distance separating them 2)equation for force of gravity 3)What is the universal gravitational constant 4)what is the correlation between force of gravity and distance

1) directly proportional to product of their masses inversely proportional to square of distance 2) Force= (m1 x m2)/ d^2 3)6.67 x 10^-11 4)as distance increases, force decreases by 1/d^2 (distance is 1 then force is 1, if distance is 2 then force is 1/4) *Inverse square law*

1)What is the equation of tangential speed 2)You are on a rotating platform. You sit halfway between the rotational axis and the outer edge and have a rotational speed of 20RPM and tangential speed of 2m/s. What will be the rotational and tangential speeds of your friend who sits at the outer edge? 3)Trains ride on a pair of tracks. They are the same length when going straight. But along a curve, which track is longer: the outside of the curve or the inside

1) tangential speed= radius x rotational speed [V=rw] 2)rotational speed= 20RPM (same) tangential speed of friend= 4m/s (double since he is twice as close to the outer edge as you) 3)outside

1)Conduction vs convection vs radiation 2)Why are metals excellent conductors of heat and electricity? (electrons) 3)What are poor conductors called 4)Tile is a good conductor of heat, and better than wood. So which feels colder when stopping on it, wood or tile? 5)Should iron or wood be used as a pan handle for cooking

1)*Conduction*= transfer through stationary matter by physical conduct *Convection*= transfer through movement of a fluid-->molecules transfer from molecule to another (just within the fluid) *Radiation* = electromagnetic radiation emitted or absorbed (microwaves, infrared, visible light, etc.) 2)They have the loosest outer electrons--free to carry energy by collisions throughout the metal 3)insulators-have their outer electrons firmly attached 4)tile--heat more readily conducted out of the foot touching the tile 5)wood--good insulator (iron would be hot if you touched it)

*Quiz* 1)Which is the lowest temperature a)32 degrees C b)32 F c)32 K d)all are same 2)which of the forms of molecular energy contribute to the total thermal energy of an object? a)rotational KE b)vibrational KE c)translational KE d)vibrational PE e)all of the above 3)What form of energy contributes to temperature 4)Two different blocks of unknown material have 1 kg of mass each; one is painted red, and the other is painted green. (Assume the bricks may be of different substances.) The red brick is heated to 350 K, and then put into contact with the green brick, which is at 300 K. After a while, the two bricks reach an equilibrium temperature of 310 K. Which of the following quantities is larger for the green brick? a)temperature change b)specific heat capacity c)heat d)all of the above

1)32K 2)all of the above 3)translational KE 4)specific heat capacity

*Quiz* 1)Two massive objects, "m1" and "m2", are a distance "d" apart from each other. At this distance, the gravitational force between them is 100 N. How much gravitational force would they experience if both masses were doubled (to "2m1" and "2m2", respectively)? 2)^What if their distance doubled but mass stays the same 3)weigh more at top of mount Everest or bottom of grand canyon? 4)Is there a place in space where gravitational forces of Earth and moon cancel out? 5)The planet Mars has two moons: Phobos and Deimos. Phobos is in a smaller orbit (i.e. closer to Mars) than Deimos is. What does this tell us about the relative speeds and orbital periods of the two moons? 6)Looking up in the sky, you see two satellites, one moving faster than the other. What can you conclude about the faster satellite? a)it's less massive b)more massive c)it is closer d)it is farther 7)How does gravity on a satellite compare to gravity on Earth's surface: slightly weaker, very weaker, slightly stronger, very stronger? Why? 8)why do astronauts float around when they are in space? a)gravity is cancelled out so net force is zero b)space stations and astronauts are in free-fall, so have no apparent weight c)no gravity in space because they are too far from Earth d)no gravity in space because space station blocks gravity's effects 9)what causes spring tides: full moon, 3/4 moon, new moon, 1/4 moon 10)for which substances does density vary the most: liquids, solids, gases 11)Two swimmers dive 1 meter below the surface of fresh water: the first swimmer is swimming in a small pond, and the other swimmer is in an enormous lake. Which swimmer experiences more pressure? 12)Why are dams built thicker on the bottom than on the top

1)400N----F=G(m1)(m2)/(d^2) 2)25 (decreases by factor of 4 is distance is doubled) 3)grand canyon--closer to center of Earth 4)Yes--but closer to moon (since Earth is more massive) 5)Phobos moves faster with smaller orbit, Deimos has larger orbital period 6)it's closer 7)slightly weaker ---only a little farther from Earth's center than the surface is 8)space station and astronauts are in free-fall, so they have no apparent weight 9)full moon and new moon 10)gases 11)NEITHER---only factor is depth (size of body of water does not matter) 12)water pressure increases with depth

1)When pushing down on a wrench: What is the optimal angle to push down 2)at 90 degree angle, which is easier to turn a bolt using a wrench: a wrench 1 foot long or 2 feet long 3)What happens if you increase the angle at which you push down on the wrench 4)If a pipe effectively extends a wrench handle to three times its length, by how much will the torque increase for the same applied force? 5)A see saw is balanced. Suddenly, the girl on the left is handed a bag of apples and gains 50N so that the seesaw tips toward her side. Which direction should she move so that the see saw does not tip

1)90 degrees 2) 2 feet long--provides more torque (makes it easier to rotate the wrench) 3)increase angle = shorter lever arm = less torque= harder to push 4) 3 times--easier to push down 5)closer to the person on the opposite side--provides less torque so torques will be balanced

1)Freezing point of water for Celsius vs Fahrenheit vs Kelvin 2)^boiling point 3)^absolute zero

1)Celsius= 0 F= 32 K= 273 2)C=100 F=212 K=373 3)C= -273 F= -459 K=0

1)If you roll a tapered cup across a surface, what shape of path does it make and why

1)Curved path---the wider part of the cup (the open part) has a greater radius and rolls a greater distance per revolution; therefore, it has a greater tangential speed than the narrower end (the bottom of the cup)

1)True or false: The space shuttle orbits at altitudes in excess of 150km to be above both gravity and Earth's atmosphere 2)a ball launched into the air at 45 degrees to the horizontal initially has: a)equal horizontal and vertical components b)components that do not change in flight c)components that affect each other throughout flight d)a greater horizontal component of velocity than vertically 3)when no air resistance acts on a projectile, its horizontal acceleration is a)g b)right angle to g c)centripetal d)zero 4)When you toss a projectile horizontally, it curves as it falls. It will be an Earth satellite if the curve it makes: a)matches the curve of planet Earth b)results in a straight line c)spirals out indefinitely d)none of these 5)A satellite in circular orbit travels at a _____ speed, and a satellite in an elliptical orbit travels at a _______ speed a)fast, slow b)slow, fast c)constant, variable d)variable, constant

1)FALSE---above AIR DRAG, not gravity 2)equal horizontal and vertical components ---not C because horizontal is always constant (x and y components are independent of each other) 3)zero 4)matches the curve of the planet Earth 5)constant, variable

1)Describe condensation at a molecular level 2)is this a cooling or warming process 3)What is worse: steam burn or burn from boiling water 4)If you left a bucket of water out and the next morning the level was still the same, can you conclude that evaporation was not happening?

1)Gas molecules near surface of liquid are attracted to liquid, and strike it with increased KE and become part of the liquid 2)Warming process--the excess KE is shared with the liquid, raising the temperature 3)Steam burn--steam releases a lot of KE when hitting skin as it condenses from gas to liquid; warming sensation a lot higher 4)NO--can be having condensation and evaporation at same time that cancel out

1)Why does the force of gravity change the speed of a satellite when it is in an elliptical orbit but not when it is in a circular orbit 2)From the surface of the Earth, what is the velocity needed for a projectile to outrun gravity and escape the Earth (escape velocity) *Thrown at 8km/s--will return from orbit in 90min in circular path; at above 8km/s, will go on elliptical path and take longer than 90min to return; thrown at 11.2km/s or more, will never complete orbit as it will escape Earth* 3)When a projectile achieves escape speed from Earth, it will: a)forever leave Earth's gravitational field b)outrun the influence of Earth's gravity, but is never beyond it c)come to an eventual stop, returning to Earth at some future time d)all of the above

1)In elliptical orbit, satellite moves in directions that are NOT perpendicular to the force of gravity so there is differing amounts of force of gravity which changes speed (has horizontal and vertical components of force) --in circular paths, has same force of gravity all around 2)11.2km/s 3) B. outruns the influence of Earth's gravity, but its never beyond it

1)Describe how evaporation works at a molecular level 2)Is evaporation a heating or cooling process 3)What is sublimation

1)Molecules at surface of liquid gain KE (with heat) by being bumped from molecules below (translational energy), which can cause them to have enough KE to lead surface and fly into space above liquid and become vapor 2)Cooling--the KE of the molecules in the liquid is lowered 3)molecules bumped directly from solid to gaseous phase (i.e. frozen water evaporating--dry ice)

1)In the desert, the daytime can be really hot and nighttime is really cold. The walls of houses are made of mud. Why must the walls made of mud be thick? 2)why can you place your hand inside a hot oven and not be burned, but once you touch the metal you are burned?

1)Slows heat flowing from inside to outside (keeps it warm) in the night, and in the day it slows the flow of heat from outside to inside (keeps it cooler) 2)Air is a poor conductor of heat--heat will not travel well between hot air and hand; The metal is a great conductor of heat so the heat will flow largely from the metal to hand

1)Force tends to change the motion of things. What does torque change? 2)what is applied to make stationary object move vs rotate 3)equation for torque 4)On see-saw: Torque of girl sitting 3m away from midpoint with 250N force vs boy sitting 1.5m away with 500N force 5)^ will the see saw go toward the boy or girl 6)What would happen if the boy moved from 1.5m away to 3 meters away

1)Torque twists/changes the state of rotation of things 2)move= force; rotate= torque 3)torque= lever arm x force (lever arm= shortest distance between applied force and rotational axis) 4)SAME--torque= lever arm x force = 250 x 3= 500 x 1.5 = 750nM 5)neither because they have the same torque 6)see saw would dip toward his side (his torque would be 1500nM and the girl's would only be 750nm)---to counter this, the girl would have to move back as well

1)a baseball is batted at an angle into the air. Once airborne, and neglecting air drag, what is the ball's acceleration vertically? Horizontally? 2)At what part of its trajectory does the baseball have minimum speed 3)When air drag is small enough to be negligible, how will the time it takes for a projectile to rise to its maximum height compare to time it takes to fall from that highest point to its initial level? 4)what is the equation for distance between the height a projectile would be if launched if there was no gravity and the height that a projectile actually is due to gravity

1)Vertical acceleration= 10 (G) Horizonal= 0 (no horizontal force acting on ball) 2)at the top (will be zero) 3)Will be the SAME (deceleration by gravity going up is same as acceleration by gravity coming down) 4)d= 5(t^2) ----ex)after 3 seconds, the distance between straight line path without gravity vs parabolic path with gravity is 45meters; 5 times 3^2 is 45 *This equation is for when air drag is neglected and does not depend on angle of cannon*

1)parabolic path: acceleration occurs in which direction? Constant speed occurs in which direction? 2)how does velocity change going up vs down? where is velocity the least? When is it zero? 3)Which component increases when you increase angle? Which component increases when you decrease angle? 4)Assuming negligible air resistance, the horizontal component along the path of the projectile: a)increases b)decreases c)remains the same d)not enough information 5)When is the horizontal range of two different angles the same when shot at same speed (hint: angles) 6)Assuming negligible air resistance, how can the range be maximized 7)^ what about with air resistance for small vs large objects (golf ball vs javelin)

1)acceleration= vertical direction constant speed= horizontal direction 2)decreases going up, increases going down, minimum at peak, NEVER ZERO 3)Higher angle= higher Vertical, lower horizontal Lower angle= lower vertical, higher horizontal 4) C. remains the same -->no horizontal force= no horizontal acceleration 5)when the angles of the two projectiles sum to 90 (ex: ball shot at 75 degrees and 15 degrees has same horizontal range) 6)launch it at 45 degrees 7)small objects like golf balls: launch at a little less than 45 degrees large objects like javelins= still at 45 degrees

1)The process of boiling: a)cools the water being boiled b)depends on atmospheric pressure c)is a change of phase below the water surface d)all of the above 2)When snow forms in clouds, the surrounding air is: a)cooled b)warmed c)insulated d)thermally conducted 3)Ice is put in a picnic cooler. To speed up the cooling of cans of beverage, it is important that the ice: a)melts b)is prevented from melting c)be in large chunks d)none of the above

1)all of the above 2)warmed---change of phase is from gas to solid, which releases energy and therefore warms the air molecules 3)melts---When going from solid to liquid, energy is required and therefore taken/absorbed from the drink; when the drink loses energy, it is cooled

1)if one object thrown at 30m/s falls 5m after 1 second, how far will an object fall thrown at 60m/s? 2)Based on the curvature of the Earth, how fast do you need to throw a ball so that it doesn't hit the Earth? 3)^ if you throw an object that fast, it will burn due to friction from air drag. How fast do space shuttles travel to prevent crashing into Earth and how come they do not burn 4)When a satellite travels at a constant speed, the shape of its path is: a)circle b)eclipse c)oval that is almost elliptical d)circle with square corner

1)also 5m/s--speed does not effect distance falling; d=5(t^2) 2)8000m/s or 8km/s (surface of the Earth drops a vertical distance of 5 meters for every 8km tangent to the surface) 3)they travel at 8km/second--do not burn because launched 150km above the Earth where there is no air drag 4)circle

1)What is Archimedes' Principle 2)how does depth effect whether an object will sink? 3)why do life jackets help you float

1)an immersed body is buoyed up by a force equal to the weight of the fluid it displaces (buoyant force equal to weight of displaced water)---applies to fluids (gases and liquids) 2)it does not have an effect---anything more dense than water will sink 3)it increases volume without adding weight, which therefore decreases density (density= weight/volume)

1)what is a charged atom called 2)a positive ion has an excess or deficiency of electrons? 3)What are atoms of the same element with different numbers of neutrons called? 4)what is the mass number of an iron isotope with 26 protons and 30 neutrons 5)how do the behavior of isotopes differ

1)an ion 2)deficiency of electrons 3)isotopes 4)56 5)they behave identically

1)What moves faster on merry-go-round: horse near outside rail or near inside rail 2)Circular motion--is this tangential or rotational 3)Which involves the number of rotations or revolutions per minute 4)relationship/correlation between tangential speed, radial distance and rotational speed

1)angular/rotational speed= same linear speed= outside 2)tangential (linear) 3)rotational speed (angular speed) 4)tangential is directly proportional to radial distance and rotational speed

*Atomic structure* 1)where is the concentration of nearly all the mass 2)what is the building block of the nucleus 3)what are 4 characteristics of atoms 4)which of the following are *incorrect* statements about the atom? a)atoms are smaller b)atoms are mostly empty space, just as the solar system is mostly empty space c)atoms are perpetually moving d)atoms are manufactured in plants and in humans e)all are correct 5)how many kinds of atoms are elements made of 6)how many elements are known 7)what are the 5 compositions of living things (5 elements)

1)atomic nucleus 2)nucleons (protons-positive, neutrons-neutral) 3)incredibly tiny, numerous, perpetually in motion, ageless 4)D 5)only one (atom and element used interchangeable) 6)115--90 in nature 7)oxygen, carbon, hydrogen, nitrogen, calcium

1)How is boiling different than evaporation 2)How can boiling occur without heat *Boiling requires the pressure of the vapor within the boiling bubbles to be greater than the pressure of the surrounding liquid. Therefore, increasing pressure requires vapor molecules to move faster to exert enough pressure to prevent bubble from collapsing.* 3)Why can boiling occur less than 100 degrees C at higher altitude 4)Is boiling a cooling or heating process 5)what happens if you boil water for too too long

1)boiling occurs throughout the liquid, evaporation is only at the surface 2)if you remove all the pressure from air, it will boil (i.e in a vacuum) 3)higher altitude= less air pressure-->therefore, can boil at lower temp since vapor molecules do not have to move as fast *with pressure cooker, pressure inside is increased so molecules need to be moved even faster and therefore requires more than 100 degrees C* 4)Cooling---boiling removes heat from water left in container, so it is cooled to a lower temperature 5)it will turn into ice

1)What is the average position of all the mass that makes up the object 2)what is the average position of weight distribution 3)true or false: center of gravity and center of mass refer to same point 4)where is the center of mass of a doughnut 5)when you toss a baseball bat in the air, what point will it rotate/wobble around? 6)when you throw a baseball in the air, it will follow a smooth parabolic trajectory. Why? 7)can an object have more than one center of mass

1)center of mass 2)center of gravity 3)true (usually) 4)in the middle of the hole 5)center of mass 6)its center of mass is at its geometrical center 7)no

1)What is the apparent outward force called 2)does centrifugal force pull outward or inward 3)what keeps the water inside the bucket when you whirl it in a circle 4)^what if you cut the string as you whirl it--which direction will the bucket go

1)centrifugal force 2)neither--does not actually pull 3)centrifugal force 4)continues along straight line path and *not* outward ---no force acts on it so continues on tangent straight-line path

1)what is Pascal's principle? *review lecture 14 slide 41 for hydraulic press* 2)What is the contractive tendency of the surface of liquids 3)how does more area of an object effect surface tension

1)change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid 2)surface tension 3)more area= more buoyant force--breaks surface tension

1)What is an adiabatic process 2)What are the two adiabatic conditions? 3)In adiabatic processes, what is an increase in IE equal to? Is it cooler or warmer? 4) ^decrease in IE? Is it cooler or warmer 5)Why does a bicycle pump get warmer when air is compressed

1)compressing or expanding a gas while no heat enters or leaves the system 2)thermally insulating a system from its surroundings or perform process so rapidly that heat has no time to enter or leave 3)work done ON system--system is warmer 4)work done BY system--system is cooler 5)you do work ON the pump which therefore increases its IE and therefore gets warmer

1)How do heat engines work 2)What is entropy and how does it correlate to degradation of energy

1)contains a reservoir of heat and sink at low temperature; the heat engine gathers heat from the reservoir and increases the IE of the engine--converts some of the heat into mechanical work and expels the rest of the heat to sink at lower temperature 2)measure of the amount of disorder in a system--higher entropy means more degradation of energy

1)how does density of air vary with altitude 2)why doesn't the pressure of the atmosphere break windows 3)^ what would happen if a tornado passes by 4)Why do champagne bottle caps explode

1)decreases as you go higher 2)atmospheric pressure exerted on both sides of window, so it experiences no net force 3)air pressure would be reduced causing the building to explode 4)the pressure inside is greater than that of the outside

1)Bernoulli's Principle: Where the speed of a fluid increases, how does the internal pressure in the fluid change 2)Why do trucks passing closely on a highway become drawn to each other 3)how can a roof be lifted off with wind

1)decreases---higher speed= less internal pressure 2)air pressure between the trucks is less than pressure on their outer sides pushing inward--therefore, trucks go inward 3)the wind causes a reduction in pressure, meaning that the pressure inside the house will be greater than outside pressure, so roof will blow off

1)Newton's Law of cooling states that cooling is proportional to what? 2)What cools faster: Hot apple pit in freezer or on kitchen table at room temperature 3)Why does the Earth stay warm and why is there global warming?

1)difference in temperature 2)in freezer--cools faster because has larger temp difference 3)Earth emits long-wave radiation (sun is short-wave) which prevents radiant energy/heat from escaping Earth's atmosphere---global warming because greenhouse gases further trap too much energy and make Earth too warm

1)What are ocean tides caused by 2)Which side of the Earth is there a stronger gravitational force between the moon and the Earth (side nearer to moon or farther from moon) 3)How many ocean tides are there per day and why do they not occur at the same time every day 4)true or false: only the moon causes tides 5)what are spring tides, what are they caused by, and when do they occur (in terms of moon phase) 6)what are neap tides and what are they caused by? When do they occur in terms of moon phase?

1)differences in the gravitational pull between the moon and the Earth on opposite sides of Earth 2)closer to moon---gravitational force weakens with increased distance 3)two tides per day---not at same time because the cycle is at 24 hour, 50 minute intervals 4)FALSE; the sun also contributes but only half as much as moon because the sun is farther 5)higher-than-average high tides and lower than-average low tides; caused by alignment of sun, Earth, and moon; occur during new or full moon 6)lower than average high tides (and vice versa) caused by moon and sun partly cancelling each other; occurs when moon is halfway between new and full

1)relationship/correlation between object's mass concentration + axis and rotational inertia 2)Which is easier to rotate: a dumbbell with the weights close to each other, or a barbell with weights at the end of each side 3)Why do circus tightrope walkers carry a long pole

1)directly proportional---higher distance between mass concentration and axis= higher rotational inertia 2)dumbbell with weights close together 3)Much of the mass of the pole is farther from the axis of rotation (midpoint) and therefore provides a lot of rotational inertia--prevents person from rotating/falling over by allowing enough time for person to adjust balance

1)How can you determine the stability of an object? 2)how does the Leaning Tower of Pisa not fall 3)what can cause a drawer to topple over when you pull out one of the drawers

1)draw a line straight down from the center of gravity of an object---it will be stable if this line falls inside the base of the object 2)it is in stable equilibrium---its center of gravity lies above the base of the tower *farther away CM is from the base, the more unstable it will be* 3)the CG may shift to go beyond its support base, causing it to topple over

1)What causes convection and in what states of matter does it occur in 2)How does boiling water work 3)Why can you hold your fingers beside a candle flame but not above it

1)due to motion of fluid itself--occurs in fluids only (liquids and gases) 2)When heated from bottom, molecules at bottom gain KE and move faster and spread apart and are buoyed up. Then, the cooler water above it moves down to fill its place and the cycle continues 3)hot air moves up, not really sideways

1)Which of the following has the smallest mass? a)proton b)neutron c)electron d)all have about the same mass 2)an element is a substance consisting of: a)atoms of the same kind b)atoms or molecules of the same kind c)only protons d)protons and electrons in balance 3)the atomic number of an atom is defined in terms of its number of a)protons b)neutrons c)protons and neutrons d)protons, neutrons, electrons 4)atoms combine to form molecules by way of a)nuclear forces b)electrical repulsion c)shared or exchanged electrons d)neutron attractions 5)if you add or subtract a proton to or from the nucleus of an atom, you produce: a)completely different atom b)an isotope of the same atom c)an ion d)none of the above 6)The atoms in isotopes of a particular element have different numbers of: a)electrons b)protons c)neutrons d)electric charges 7)isotopes of a given element differ in: a)atomic number b)mass number c)electron number d)their place in the periodic table

1)electron 2)atoms of the same kind 3)protons 4)shared or exchanged electrons 5)a completely different atom 6)neutrons 7)mass number

1)If you double the speed at which you round a bend in the curve, by what factor must the centripetal force change to prevent you from skidding?

1)four times *double speed = 4x centripetal force*

1)Why is there an overflow of gasoline from a car's tank on a hot day? 2)Why does ice float on water (crystalline structure) 3)When 0 degree C water is heated, it will first: --and why/up to what point? a)expand b)contract c)remain unchanged d)not enough info 4)When 4 degree C water is cooled, it will: --and why? a)expand b)contract c)remain unchanged d)not enough info 5)What happens when water reaches above 4 degree C (expand, contract, remain unchanged)

1)gasoline underground is cool, but when placed in car's tank, it warms and expands 2)between 0 and 4 degrees C, has a crystalline structure with opened structured crystals; with this structure, they occupy greater volume than they do in liquid phase and therefore is less dense than water (because D=m/v, and higher V means lower density) 3)contracts-->does so until reaches 4 degrees C, of which water will then expand *at 0 degrees, it has crystallized structure; When warmed to 4 degrees, the crystals will collapse resulting in smaller volume of liquid water* 4)expand--because parts of water will crystallize and occupy more space 5)expand as it is heated because of greater molecule motion

1)if standing on scale, what happens if you are in an elevator going up? Going down? Cutting cable and elevator falls? 2)when in weightless condition, is there still gravitational force acting on you? Why/why not can you/can you not feel the weight? 3)Describe the condition of astronauts (free fall)

1)going up--weight reading is greater down--weight is less falling--*weightless* 2)Yes--causing downward acceleration but is not felt due to lack of support force (upward force) 3)they are sustained in a state of weightlessness due to lack of support force---*in orbit, they are in a state of continual free fall*

1)Two blocks of different materials are dropped into cups of water. Both blocks sink, and when they do they displace the same amount of water. What does this tell you about the two blocks? a)they have same volume b)have same mass c)have same density d)all of above

1)have the same volume

1)What is the first law of thermodynamics 2)what does head added to a system lead to 3)how does adding heat affect IE, heat, and KE *Heat added= increase in internal energy + work done*

1)heat added to a system transforms to an equal amount of some other form of energy (Heat cannot be created nor destroyed) 2)increase in internal energy (IE) and work done by system 3)eat increases IE and therefore increases heat and therefore the KE of the molecules

1)In projectile motion, which component (horizontal or vertical) of velocity remains constant? 2)At the instant a cannon fires a cannonball horizontally over a level range, another cannonball is held at the side of the cannon is released and drops to the ground. Which ball, the one fired downrange or the one dropped from rest, strikes the ground first? Why? 3)How does launching at an upward angle vs downward angle affect the vertical distance of fall?

1)horizontal component 2)both hit ground at same time--both fall same vertical distance 3)it does not make a difference *vertical distance is independent of what's happening horizontally*

*Radiation* 1)How does increasing heat effect electromagnetic waves 2)relationship between wavelength and frequency 3)^ between wavelength and heat 4)^ between heat and frequency 5)Do all substances at any temperature emit radiant energy? 6)True or false: only the sun, not the Earth emits radiant energy

1)increase heat= increase frequency= decrease wavelength 2)increase frequency= decrease wavelength 3)increase heat= decrease wavelength 4)directly proportional 5)yes, unless they are at absolute zero 6)False; both emit radiant energy, but the sun emits far more energy at a higher frequency

1)If 100J of heat is added to a system that does no external work, by how much is the internal energy of that system raised? 2)If 100J of heat is added to a system that does 40J of external work, by how much is the internal energy of that system raised? 3)How can a system have an increase in temperature without adding heat?

1)increases by 100J 2)60J-----100J= (increase in internal energy) + 40J; therefore, 100-40 is 60 which is how much the internal energy is increased by 3)work can be done ON the system, leading to increase in internal energy which therefore leads to increase in temperature

1)Boyle's Law: what is the correlation between pressure and volume of a gas enclosed in a space 2)Is there a buoyant force acting on you? If there is, why are you not buoyed up by this force? 3)in terms of air displacement, what is the buoyant force equal to 4)when weight of air displaced by an object is greater than the weight of the object, will it rise, sink, or hover in air 5)when will a gas-filled balloon continue to rise until

1)inversely proportional--increase pressure= decrease volume by same factor-->double volume=half pressure 2)yes we are buoyed up by it---don't notice because our weight is so much greater 3)weight of air displaced by object 4)rises 5)will rise until weight of displaced air equals the total weight of the balloon/the buoyant force on balloon equals its weight

1)When you whirl a tin can at the end of a string in a circle, which direction is the force acting on the tin? What is this called? 2)What is the equation of centripetal force 3)Why doesn't a car skid off the road when rounding a curve (assuming it is not going too fast and road isn't wet)

1)inward---called centripetal force (force directed toward a fixed center) 2) (mass x tangential speed^2)/radius 3)centripetal force

1)What is a temperature inversion 2)What is the second law of thermodynamics 3)how can heat flow from cold to hot (work) 4)What does a heat engine convert

1)large parcels of cold air sink and remain at low level; air above is warmer and traps the cold air 2)heat never flows spontaneously from cold object to hot 3)work must be done ON system by adding energy from another source such as heat pumps or air conditioners 4)converts internal energy into mechanical work

1)What is the equation for liquid pressure 2)deeper into water= more or less pressure 3)equation for TOTAL pressure of a liquid

1)liquid pressure= weight density x depth 2)more pressure; double depth= double pressure 3)total liquid pressure= (weight x depth) + pressure of atmosphere

1)What determines density of materials 2)what is density and what is the equation for it 3)what is the property of a material wherein it changes shape when a deforming force acts upon it, and returns to its original shape when the force is removed? 4)What is Hooke's Law and its equation

1)masses of the atoms and spacing between them 2)amount of mass per unit volume of a material; density= mass/volume 3)Elasticity 4)extension of a spring directly proportional to force applied to it (force= extension---force= change in x)

1)What is a substance that is mixed together without chemically bonding 2)what do atoms of different elements form when they bond together? 3)what is a molecule made of 4)do combining atoms release or absorb energy

1)mixture (ex: air) 2)compound--separated only by chemical means 3)two or more atoms bonded together (ex: ammonia-NH3, is made of 3 atoms of H and 1 atom of N 4)release

1)Where is the Earth's gravitational field the strongest? 2)is there a point in space where there is no gravitational force 3)is there a point in Earth where there is no gravitational force 4)why is the Earth round

1)near the center of the Earth 2)no 3)yes--in the center of the Earth 4)universal gravitation---everything attracts everything else so the Earth has attracted itself together as far as it can; the "corners" of the Earth have been pulled in so every part of the surface has equal distance from the center of gravity making it a sphere

1)positive attracts negative and positive repel positive---why doesn't the nucleus "explode" then if positive repels positive?

1)neutrons keep space between protons so they do not repel

*Periodic table* 1)What determines atomic number 2)number of protons vs electrons in neutral element 3)What is a special characteristic of noble gases 4)What determines mass number 5)in neutral element, if the atomic mass of carbon is 12, what is the atomic number?

1)number of protons in nucleus (arranged from left to right, with right having one more proton than left) 2)the same 3)outer shells are filled to capacity 4)number of protons AND neutrons 5)6---6 protons, 6 neutrons (and 6 electrons but this is not factored into atomic mass)

1)What is an electrified gas composed of atoms that are ionized 2)Which states of matter are made of ions vs atoms 3)objects are pushed toward area of more or less pressure

1)plasma 2)atoms= solids, liquids, gases ions= plasma 3)less pressure

1)is air a good or poor conductor of heat 2)How do animals stay warm in snow 3)How can snow keep the ground warm in winter 4)True or false: a house gets cold in the winter because cold enters

1)poor conductor 2)their fur traps more air so that the environment won't effect their body 3)Snow is a poor conductor and therefore a GOOD INSULATOR--it slows down the loss of heat 4)FALSE_--gets cold because heat leaves; this is countered by having insulators to slow down the loss of heat (insulators prevent heat from escaping)

1)How does warmth occur 2)is temperature related to translational or rotational energy 3)^ translational vs rotational KE 4)how does rotational energy effect temperature

1)random motion of atoms/molecules gain kinetic energy causing atoms to jostle faster-->warmer 2)translational KE 3)translational= motion that carries molecule from one place to another Rotational= molecule rotating or vibrtating 4)does not--only translational does

*Specific Heat Capacity* 1)what is thermal inertia 2)what is specific heat capacity 3)correlation between specific heat capacity and time it takes to boil 4)^time it takes to cool 5)why is water a useful cooling agent

1)resistance of a substance to change its temperature 2)quantity of heat required to change temperature of a unit of mass by 1 degree 3)directly proportional (higher specific heat capacity= longer time to boil) 4)directly proportional 5)has high specific heat capacity---hot engines will not make water too hot and will cool down the engine

*Quiz* 1)Gravity can be simulated for astronauts in outer space if their habitat: is very close to earth, is in free fall about earth, rotates, or revolves around earth? 2)For an object traveling in a circular path, its angular momentum doubles when its: linear speed doubles and radius remains the same, radius doubles and its linear speed remains the same, mass doubles and linear speed and radius remain the same, or all of the above 3)A car travels in a circle at constant speed. What is the net force on the car? 4)During the "spin cycle," a clothes dryer spins around quickly to separate water from the clothing. (Water is allowed to pass through holes in the outside drum of the dryer, which are too small for the clothes to fit through.) What are the directions of the forces acting on the clothing and the water during this process? a)no force on the clothes, outward on the water b)inward on the clothes and outward on the water c)inward on the clothes, no force on water 5)a rock tied to a swing is swung in a horizontal circle. If its speed is doubled, how will that that affect the tension in the string (reduced, doubled, tripled, stay the same, quadrupled) 6)You are riding in a car as it goes around a circle very fast. You slide across your seat, and slam into the car door. As observed by someone outside the car, which force (if any) was responsible for this motion? a)centripetal force b)centrifugal force c)both centrifugal and centripetal d)no force; to them, you move in a straight line 7)Which horses have the greatest liner speed on a carousel? Near the edge or toward the center? What about angular speed? 8)angular speed of a large diameter wheel vs smaller diameter wheel? Which rotates faster? *Torque= perpendicular distance from rotational axis to line along which force acts* 9)Two people are balanced on a seesaw. If one person leans inward toward the center of the seesaw, that person's end of the seesaw tends to: a)rise b)fall c)stay on same level d)need more info

1)rotates 2)all of the above 3)toward the center of the curve (inward) 4) c. inward on clothes, no force on water 5)quadrupled 6)no force; to them, you move in a straight line 7)linear speed: near the edge angular speed: same for all horses 8)smaller diameter wheel has more angular speed--rotates faster 9)rise

1)solids vs liquids vs gases: which have definite volume but variable shape, definite shape and specific volume, and neither definite shape nor specific volume 2)What is the equation for pressure 3)which has more pressure: upright block, or block on its side 4)how does area correlate with pressure 5)when you stand on one foot instead of two, the force you exert on the floor is: a)less b)the same c)more d)none of the above 6)^pressure

1)solids= definite shape and specific volume liquids= definite volume but shape changes gases= neither definite shape nor specific volume 2)pressure= force/area (unit= pascals) 3)upright block because has less area 4)smaller area= higher pressure 5)the same *force* 6)more *pressure* (double pressure in this case)

1)How does KE effect molecules 2)What is atmospheric pressure caused by? 3)true or false: atmosphere pressure is the same in every location 4)air thinner or thicker when you go higher 5)why do we not feel the weight of atmospheric pressure against our bodies

1)spreads the molecules apart 2)weight of air 3)false--not uniform 4)higher= thinner 5)pressure inside our bodies equals that of surrounding air--no net force sensed

1)why can arches be used in place of columns for building support 2)Why can't an ant that grows extremely large be stronger than an elephant (given that an ant can carry another ant on its back but an elephant cannot) 3)relative to its weight, what is stronger: a toothpick or a tree 4)cross-sectional area and strength grow as the same proportion, square, or cube of increase? Volume and weight? 5)Question: cube has side length of 1- its area is 1, volume is 1, and mass is 1. What would these values be if the length grows to 2?

1)stone can withstand compression---the compression strengthens the structure as the stones are pushed together more firmly and held together by compressing forces; they can carry more top-side weight 2)it grows heavier faster than it grows stronger--ant growing that big would be unable to lift its own weight off the ground as its legs would be too thin for greater weight 3)toothpick 4)cross-sectional area and strength= grow as *square* of increase volume and weight= grow as *cube* of increase 5)area=4, volume=8, mass=8 *Therefore, volume/weight grows faster than area/strength*---both increase, but volume/weight increases faster

1)What is a person experiencing when they are on a rotating platform that speeds up slows down 2)What is the property of an object to resist changes in its rotational state of motion 3)^ remains in that motion unless interfered with by some _____

1)tangential acceleration--change in tangential speed 2)rotational inertia 3)external influence--*Torque*

1)how does temperature and experienced pressure change as parcels of air rise 2)how long will air continue to rise and expand 3)When gas expands, does temperature increase or decrease? Compresses? 4)Where is work done when gas adiabatically expands? 5)How does volume of gas effect temperature

1)temperature drops (10C every 1 km rise) and air pressure lowers 2)as long as it has higher temperature than its surroundings--when it gets cooler than its surroundings, it sinks 3) Expands= temp DECREASE Compresses= temp INCREASES 4)work is done on its surroundings, releasing IE as the gas becomes cooler 5)increase volume = expands = work done BY system = temp decreases

1)tension vs compression 2)Why does construction use an I-beam (2 reasons) 3)If you were to drill a hole horizontally through a tree branch, where will the hole weaken the branch the least and why?

1)tension= stretching/pulling (such as pulling rope) compression= squeezing 2)maximizes strength---top (under tension) and bottom (under compression) have most material minimizes weight--middle of the beam not under stress has the least material 3)near the middle---the stress is at the top and bottom part (that are under tension and compression) with no stress in the middle

1)How can gravity be simulated in a space station 2)when you whirl a tin can in a horizontal circle overhead, the force that holds the can in the circular path acts: inward, outward, either one, or parallel to force of gravity?

1)the space station can be spun extremely fast, causing the astronauts to experience centrifugal force and stay on the ground--simulated gravity 2)inward

1)You place an object in a container that is filled to the brim with water on a scale. The object floats but some water spills out. How does the weight of the object compare with the weight of the water displaced? a)weight of water is greater than weight of water displaced b)less than c)equal to d)not enough info to decide

1)the weight of object is *equal to* weight of water displaced

1)how do microwaves work? Is food cooked by translational or rotational energy 2)What makes up internal energy (sum of what?) 3)Which will transfer more heat to a cooler substance: bucket of hot water or cup of hot water? 4)^which one's temperature will increases more when adding 50 degree water

1)translational--translational KE is imparted to neighboring molecules that are bounced off by oscillating water molecules (oscillate due to rotational KE---but rotational KE alone does not cook food) 2)internal energy= total KE + total PE (KE due to motions relative to each other, PE due to positions relative to each other) 3)bucket 4)cupful--temp increases more in container with smaller amount of water

1)According to Hooke's Law, if you hang by a tree branch and note how much it bends, then hanging with twice the weight normally produces: a)half the bend b)the same bend c)twice the bend d)four times the bend 2)When you sit in the middle of a horizontal bench supported at its ends, the top side of the bench is a)under tension and bottom side under compression b)compressed and the bottom is stretched c)compressed and the neutral region in between is compressed d)all of these 3)if Sally shrinks to one-tenth her size, the ratio of her surface area/volume will: a)increase b)decrease c)remain the same d)none of the above

1)twice the bend (f=change in x, so double F means double X/bend) 2)the top is compressed and the bottom is stretched 3)increase---surface area and volume decrease but ratio surface area/volume increases (decreases when size increases)

1)How does a cloud occur(about 6 steps) 2)How does fog occur (about 5 steps)

1)warm air rises--it expands and chills--water-vapor molecules are slowed---they stick together (condensation)--form cloud 2)most air moves from warm water to cool water/warm water to cool land--moist air chills--water-vapor molecules stick together--condensation takes place near ground level *^main difference is altitude--fog is a cloud that has condensation near the ground*

1)is water warmer or colder than air in the winter 2)does heat cause compression or expansion 3)bimetallic strip of brass and iron: When temperature is increased, is there a greater expansion for brass or iron side 4)is thermal expansion greater in liquids or solids

1)warmer in winter, cooler in summer---temp does not vary much from summer to winter due to high specific heat capacity 2)expansion (wires become long and saggy) 3)brass 4)liquids

1)How does melting occur at molecular level 2)What about freezing

1)when heat is applied, there is added vibration that breaks molecules loose from structure and melting occurs 2)energy is continually removed, causing decrease in molecular motion until they the molecules bind together and form solid ice *Solid to liquid= add energy; Gas to Liquid= Remove energy*

1)Why is it easy to lift a boulder that is below the water surface 2)when will an object sink 3)when will an object neither sink nor float 4)how many forces act on a submerged body at rest in a fluid?

1)when the bolder is submerged, it undergoes an upward force---*buoyant force* ; upward forces against the bottom are greater than downward forces against the top 2)if its weight is greater than the buoyant force 3)when the weight of the submerged object is equal to the buoyant force 4)Two--buoyancy AND force due to gravity

1)if you apply a flame to 1L of water for a certain time and its temp increases by 2 degrees, what would happen if you did the same thing for 2 L of water (how much will temp rise) 2)You heat a half-cup of tea and its temp raises by 4 degrees. How much will the temp rise if you add the same amount of heat to a full cup of tea

1)will rise only by 1 degree because there a 2x as many molecules in 2L of water 2)2 degrees

1)Path of a tossed object with gravity vs without gravity 2)why does the path with gravity happen 3)what is projectile motion a combination of 4)Projectile motion: what happens if there is no friction? 5)describe the vertical component

1)without gravity= straight-line path; with gravity=curved path 2)continues motion by its own inertia 3)horizontal component and vertical component 4)there is no horizontal force and velocity is constant--covers equal distances in equal intervals 5)same as free fall---faster it falls, greater distance covered in each successive second (vertical positions become farther apart with time)

1)Why do you run faster if your legs are bent 2)how do long baseball bats compare with short baseball bats (rotational inertia) 4)What will roll down faster down a hill from rest and why: a solid cylinder or a hoop 5)rank from most rotational inertia to least: hoop, solid cylinder, simple pendulum, solid sphere

1)you reduce their rotational inertia so you can rotate them back and forth more quickly 2)long baseball bats have more rotational inertia so it is harder to make it start swinging; however, once you start swinging it will keep on going 4)solid cylinder---because a hoop has more of its mass far from the axis, giving it more rotational inertia 5)simple pendulum, solid sphere, solid cylinder, hoop

5)What is the volume of water displaced by an object equal to?

5)the volume of the object---helps determine volume of irregularly shaped object

6)What is easier to balance: a hammer with the handle on your hand, or a hammer with the head on your hand (basically upside down hammer or right side up hammer)

6)right side up hammer (head at top, handle on hand)---most of its mass is away from hand so has more rotational inertia)

A block of Styrofoam and a block of lead are the same size. When dropped in the water, the Styrofoam block floats while the lead block sinks. a)which block displaces more water b)which block experiences more buoyant force c)buoyant force on foam block is more than, less than, or equal to its weight c)^ lead block

a)lead block b)lead block c)equal to d)less than