physics final
A car was running with velocity 90 m/s. When driver saw a baby on the road, he applied brake and thecar stopped after 3 seconds. What is the average acceleration of the car?
-30 m/s
As a 70-kg person stands at the seashore gazing at the tides (which are caused by the Moon), howlarge is the gravitational force on that person due to the Moon? The mass of the Moon is 7.35 × 1022kg, the distance to the Moon is 3.82 × 108 m, and G = 6.67 × 10-11 N · m2/kg2.
0.0024 N
Consider a 100 kg Father and his 20 kg girl. They decide to enjoy balancing on a seesaw, which is a uniform board 4 m long and pivoted exactly at its center. If girl sits at the seesaw's end (2m from the center), how far from the center on the other side should the father sit?
0.4 m
A ball hits a wall going 10 m/s, and bounces off going 7 m/s. The coefficient of restitution is
0.70
In how many of the following situations does the car have a westward acceleration?
1
You and your family are on a trip to the local museum and you notice that in the aquarium there arefour fish: fish 1 is floating, fish 2 is stationary 2m below the water's surface, fish 3 is stationary 4 mbelow the water's surface and fish 4 is on the sand at bottom of the tank. (Note: things don't look goodfor fish 1 and fish 4 but that's beside the point here). Rank the densities of the fish in order ofincreasing density, including the density of water in your ranking.
1 < 2 = 3 = water < 4
Bolts work because they act like very strong springs and extend slightly when they are tightened. Suppose a steel bolt has spring constant 1.8x108 N/m. How far would it have to stretch in order to provide a force 2000N?
1.11x10-5 m
A plastic block of dimensions 2.00 cm × 3.00 cm × 4.00 cm has a mass of 30.0 g. What is its density?
1.25 g/cm3
Atmospheric pressure is about 100000 Pa. At what depth in water does this pressure double?
10 m
What is the weight of water displaced by a 100-ton floating ship?
100 tons
A 500-N weight sits on the small piston of a hydraulic machine. The small piston has an area of 2.0cm2. If the large piston has an area of 40 cm2, how much weight can the large piston support? Assumethe pistons each have negligible weight.
10000 N
The car is moving at 10 m/s relative to Bill. How fast does Amy see the car as moving?
15 m/s
If you double the absolute temperature of a star, its power output increases by a factor of
16
You push on a box with a horizontal force of 20 N and the box moves a distance of 8 m. The amount of work you have done on the box is
160 J
A scale from which a rock is suspended reads 5 N when the rock is out of water and 3 N when therock is submerged. Buoyant force on the rock is
2 N
You work in a clock shop and are dealing with an irate customer whose clock you are restoring. They notice that the period of the pendulum in their clock is 2 s and they want to double it. So they insist that you replace the pendulum with one of the same dimensions but just heavier. So you do this. When you get the clock repaired, you and the customer check out the clock's period and find it to be
2 s.
A gymnast jumps upward with an initial speed of 10 m/s. She is in the air for a total time of about
2 seconds
Suppose you do 1000 J of work on a 5 kg object, and all the work went into lifting it above the ground. How high above the ground will the object be when all the work has been done?
20 m
The temperature changes from 35°F during the night to 75°F during the day. What is the temperaturechange on the Celsius scale?
22 C°
The onset of turbulent flow happens for a Reynolds number of about
2300
What is the potential energy of a 40 kg box that is 6 m above the ground?
2400 J
During one cycle, an automobile engine takes in 12,000 J of heat and discards 9000 J of heat. What is the efficiency of this engine?
25%
How much heat is required to raise the temperature of a 225-g lead ball from 15.0°C to 25.0°C? Thespecific heat of lead is 128 J/kg · °C. (Hint: Check the proper units)
288 J
The temperature in this room is closest to
295 K.
The diagram shows a planet at four positions in its orbit. At which position the speed of the planet islowest?
3 (it's the farthest away)
If a biker rides west for 50 miles from his starting position, then turns and bikes back east 80 miles.What is his net displacement?
30 miles east
A machine uses 1000 J of electric energy to raise a heavy mass, increasing its potential energy by 300 J. What is the efficiency of this process?
30%
An ideally efficient heater adds 1100 J of heat to a warm room. How much work does it perform if it removes 1400 J of energy from the outdoors?
300 J
The following pairs of temperatures represent the temperatures of hot and cold reservoirs for heat engines. Which heat engine has the highest possible efficiency?
300°C, 30°C
You operate a 120 W light bulb for 5 minutes. How much energy did you use?
36,000 J
You are swinging a tin can around your head in a perfectly horizontal circle of radius 4 m. (This is really not possible but we're saying it almost happens.) If the speed of the can is 4 m/s what is its acceleration?
4 m/s2
Water weighs about 10 N per liter. A 4.0 liter ball is pushed underwater. What is the buoyant force onthe ball?
40 N
The brake system in most cars makes use of a hydraulic system. This system consists of a fluid filled tube connected at each end to a piston. Assume that the piston attached to the brake pedal has a cross sectional area of one half a square inch and the piston attached to the brake pad has a cross section area of two square inches. When you apply a force of 10 pounds to the piston attached to the brake pedal, the force at the brake pad will be,
40 pounds.
If you have a mass of 80 kg and are in a planet where the acceleration of gravity is 5 m/s2, your weight on the planet is
400 N
A popular playground toy is a flexible seat that has automobile springs attached to it for a little bounce. When a 200 N child sits on the toy, it compresses 5 mm downward. What is the ride's spring constant?
40000 N/m
The coefficient of restitution for a particular ball is 0.45. If he ball hits a surface traveling at 100 m/s its rebound speed will be
45 m/s
The coefficient of restitution for a particular ball is 0.45. If he ball hits a surface traveling at 100 m/sits rebound speed will be
45 m/s
The maximum height above the ground for a the gymnast jumping straight upward with an initial speed of 10 m/s is
5 m
You walk in a given direction for 20 m during the first 5 seconds of a trip and then 15 m during the next 2 seconds. Your average speed is equal to
5 m/s
A car starts from rest and accelerates at 4 m/s2. How much time will it take the car to reach a speed of 20 m/s?
5 s
What is the frequency of a vibration with period 0.02 second?
50 Hertz
In Europe an electric razor completes 50 vibrations in 1 second. The frequency of these vibrations is
50 Hz with a period of 1/50 second.
To cause a 25 kg object to experience an acceleration of 2 m/s2 the net force that needs to be applied to the object is
50 N
A heat engine receives 7000 J of heat and loses 3000 J in each cycle. What is the efficiency of this engine?
57%
What is the gravitational force that two 100 kg persons exert on each other when standing 1m apart?
6.672x10-7 N
If your mass is 60 kg on Earth, what would your mass be on the Moon?
60 kg
It is necessary to determine the specific heat of an unknown object. The mass of the object is 0.201 kg.It is determined experimentally that it takes 15.0 J to raise the temperature 10.0°C. What is thespecific heat of the object?
7.46 J/kg · °C
At a speed of 12 m/sec how far can you travel in one minute?
720 m
You are swinging a tin can around your head in a perfectly horizontal circle of radius 4 m. (This is really not possible but we're saying it almost happens.) If the speed of the can is 4 m/s and its mass is 2 kg, what inward force is required to keep the can moving in the circle?
8 N
You are bored during the summertime when school is not in session and you decide to do an experiment where you compare the properties of water and air. If the density of air is 1.25 kg/m3 and the density of water is 1000 kg/m3 , what volume of air weighs the same as 1 liter of water?
800 liters
The fundamental frequency of a violin string is 440 hertz. The frequency of its second harmonic is
880 Hz.
Suppose you weigh 986 N. How much force does the Earth exert on you, if any?
986 N
Which system is in a state of stable equilibrium?
A marble in the bottom of a spherical bowl.
Water weighs about 10 N per liter. A 4.0 kg ball floats on the water's surface. What is the weight of the water being displaced by the ball?
About 40 N
The vessels shown below all contain water to the same height. Rank them according to the pressureexerted by the water on the vessel bottoms, least to greatest.
All pressure are the same
Consider a high-speed bus colliding head-on with an innocent bug. The force of impact splatters theunfortunate bug over the windshield. Which is greater, the force on the bug or the force on the bus?
Both are the same
When a sample of 0ºC water is heated, it first
Contracts then expands.
The metric (SI) system is preferred over the British (foot-pound) system in science for the followingmain reason.
Conversions between metric quantities are especially easy because they are all related by factorsof ten.
What two properties of a material affect the speed of sound in the material?
Density and phase.
The entropy of an isolated system
Either increases or remains constant.
Which of the following quantities is not conserved?
Entropy
For momentum to be conserved in a system it must
Experience no net external force
Force and momentum are related in that:
Force is a change in momentum per unit time
Neglect air resistance in this question. If you drop a ball from a height of 4.9 m, it will hit the ground1 s later. If you fire a bullet exactly horizontally from a height of 4.9 m, it will also hit the ground 1 slater. Explain.
Gravity acts only in the vertical direction.
Consider the Moon orbiting the Earth. _______ is the centripetal force for the orbit, and one could therefore measure the mass of the ________ by studying the Moon's orbit.
Gravity; Earth
Why does the handle of a metal spoon submerged in boiling soup feel hot ?
Heat from the soup is transferred through the spoon by conduction.
Why does an ice cube feel cold?
Heat from your hand enters the cube by conduction.
Your apparent weight is equal to your weight
In an elevator not accelerating
A steady force pushes in the piston of a well-insulated cylinder. In this process, the temperature of the gas
Increases.
A Diesel engine is more efficient that a gasoline engine because
It has a higher temperature and can therefore convert more heat into work.
A child is riding a bike and skids to a stop. What happens to their kinetic energy?
It is dissipated by static friction.
Suppose you have a car traveling down the road at constant speed and not changing direction. It is experiencing gravity, wind resistance and frictional forces from the road. What can be said about the car's acceleration?
It is not accelerating because it has constant velocity.
Suppose you have a car traveling down the road at constant speed and not changing direction. It isexperiencing gravity, wind resistance and frictional forces from the road. What can be said about thecar's acceleration?
It is not accelerating because it has constant velocity.
An object is in stable equilibrium only when
Its total potential energy rises whenever it reorients.
When a fish hovers over the bottom of a lake, what forces act on it, and what is the net force?
Lift and weight, for a net force zero.
Two liquids, A and B, have equal masses and equal initial temperatures. Each is heated for the same length of time over identical burners. Afterward, liquid A is hotter than liquid B. Which has the larger specific heat?
Liquid B
Suppose you are driving your car down the highway and speeding up. Which of the following are true?
Neither the car's kinetic energy nor momentum are constant.
You are swinging a 2 kg tin can around your head in a perfectly horizontal circle of radius 1 m with a speed of 6 m/s. (This is really not possible but we're saying it almost happens.) If the string can safely exert a force of 30 N will it be able to swing the can?
No because the required force is 36 N.
What can you say about the pressures at points 1 and 2?
P1 = P2
Which type of heat transfer can happen efficiently through empty space?
Radiation
In the constellation Orion, you can easily observe thedifference between the reddish looking star Betelgeuseand the bluish looking star Rigel. Which of the two hasthe hotter surface temperature?
Rigel
It is possible for two objects of equal mass to have rotational masses because
Rotational mass depends on total mass and mass distribution in radial distance.
Which of these quantities is constant in uniform circular motion?
Speed
In which of these materials does sound travel fastest?
Steel
On a humid summer day, perspiration does not cool you off much. Why?
The air is almost saturated with water vapor and there is almost no net evaporation.
A salad spinner is a rotating basket that dries salad after washing. How does the spinner extract the water?
The apparent weight of the water is outward, forcing it through the holes in the basket.
A 2,000-kg car is sitting at rest in a parking lot. A bike and rider with a total mass of 60 kg aretraveling along a road at 10 km/h. Which system has more inertia? Why?
The car has more inertia, as its mass is greater than the mass of the bike.
Suppose you have two cars, and the larger one is twice as massive as the smaller one. If you and a friend push on them so that their accelerations are equal, how must the forces applied to the cars compare?
The force on the larger car is twice that on the smaller car.
Why must tall dams be so much thicker at their bases than at their tops?
The greater the depth of the water the greater the pressure pushing on the wall of the dam.
A difficult-to-open jar may open easily after being run under hot water for a moment. Explain.
The heat from the water makes the lid expand and loosen.
In making ice cream, the flavored cream is in a container in contact with ice. In order to freeze the ice cream why is it essential to make the ice melt at a very low temperature?
The low temperature of the ice as well as its melting removes energy from the flavored cream, causing it to freeze.
Power is
The rate at which energy is used, stored, created, dissipated, etc.
You are hired as an engineer at a thermometer factory. Suppose you built a water thermometer by replacing the mercury in a mercury thermometer with water. You want to measure temperatures above freezing with it. How would it behave as the temperature drops from 5o C to 1o C?
The reading will decrease and then begin increasing.
You are hired as an engineer at a thermometer factory. Suppose you built a water thermometer by replacing the mercury in a mercury thermometer with water. You want to measure temperatures above freezing with it. How would it behave as the temperature drops from 5o C to 1oC?
The reading will decrease and then begin increasing.
If you open the door of your refrigerator with the hope of cooling your room, you will find that theroom's temperature actually increases somewhat. Why doesn't the refrigerator remove heat from theroom?
The refrigerator releases more energy as heat than it removes from the air inside itself.
Soil heats up much faster than water when the two are exposed to sunlight. Use that fact and your understanding of heat transfer to predict which way the wind will blow near the surface of the earth as the sun rises near the seashore.
The surface wind will blow from the water toward the land.
Which of the following statements best describes the law of conservation of energy?
The total quantity of energy in the universe never changes.
Some clear toys contain two colored liquids. No matter how you tilt one of those toys, one liquidremains above the other. What keeps the upper liquid above the lower liquid?
The upper liquid is less dense than the lower liquid.
For an object that is floating on a fluid,
The weight of the fluid displaced equals the object's weight.
A spaceship is moving past us at a speed close to the speed of light. How would we view time (clocks)on the spaceship as it goes by?
Their clocks are going slower than ours.
Suppose that we are able to send astronauts to Mars and they engage in a game of golf on the red planet's surface. Given that the atmosphere on Mars is considerably less dense than our own, how will the path of the ball be affected?
There is less drag and gravity, so the ball will go further than if there were air.
When an airplane starts its propellers, they spin slowly at first and gradually pick up speed. Why doesit take so long for them to reach their full rotational speed?
They have a large rotational mass.
Why do elastic balls bounce so well?
They permanently deform, storing energy.
Suppose you are spending your weekend on roller skates trying to get momentum from somewhere. Which of the following will give you momentum in the north direction?
Throwing your keys southward.
You are riding an amusement park ride where you are strapped to the inside of a giant metal wheel that is rotating quite rapidly. Your acceleration is
Toward the center
Cities have to use water towers to supply water to because
Water pressure at the bottom of the tower is much higher than at the top.
Your dryer is broken, so you have to hang your wet clothes from the washing machine outside to dry. Under which conditions would your clothes dry fastest?
When it is 75°F with 50% relative humidity.
A 10-kg rock and a 20-kg rock are dropped at the same time and experience no significant airresistance. If the 10-kg rock falls with acceleration a, what is the acceleration of the 20-kg rock?
a
You are watching a science fiction movie where people on a space ship are traveling around theuniverse observing stars with different temperatures. Which of the following stars has the lowestsurface temperature?
a red star
Suppose you are standing on a bathroom scale when you are flying in a jet airplane. For a moment the scale reads more than your actual weight. During that moment, it's exerting an upward force on you that is greater than your weight and you are
accelerating upward.
The Bernoulli effect is responsible for the lift force on an airplane wing. Wings must therefore be designed so as to insure that
air molecules move more rapidly past the upper surface of the wing than past the lower surface.
The illustration shows a thermometer that uses a column of liquid (usually mercury or ethanol) to measure air temperature. In thermal equilibrium, this thermometer measures the temperature of
all of A, B, and C.
A metro train is traveling at constant velocity. What are the net forces on (a) the first car, (b) themiddle car, and (c) the last car?
all zero
The vibrations along a longitudinal wave move in a direction
along the wave.
Consider a flat steel plate with a hole through its center as shown in the figure. When the temperature of the plate is increased, the hole will
always expand with the plate.
The airflow around a slow-moving ball is ____ while the airflow around a fast-moving ball is ____.
aminar; turbulent
The loudness of a sound is most related to its
amplitude (intensity).
A baseball player balances a bat on his finger; the bat is laying sideways and not standing on end. The bat will balance
at its center of mass.
Your apartment window opens 20 meters (65 feet) above a lemonade stand. Your friend lowers a long plastic tube out the window until its end enters the tank of delicious lemonade far below. She then begins to suck on the other end of the tube in hopes of getting a free drink. To her dismay, she never tastes a drop because
atmospheric pressure cannot support a column of lemonade 20 meters tall.
Suppose you go from the earth to a planet where the acceleration of gravity is 2.5 m/s2. On the new planet your weight will be about
be ¼its value on Earth
A bubble of air released from the bottom of a lake
becomes larger as it rises
As shown in the figure, a bimetallic strip, consisting of metal G on the top and metal H on the bottom, is rigidly attached to a wall at the left. The coefficient of linear thermal expansion for metal G is greater than that of metal H. If the strip is uniformly heated, it will
curve downward
If the distance between planets is somehow tripled, the force of gravity between them would
decreases by one ninth
You are playing with your younger cousins and find yourself on all fours, with your hands and feet on four bathroom scales on the level ground. You took a "Physics in Everyday Life" course so you can make a reasonable guess that the reading on each scale is obtained by
dividing your mass by 4.
If the mass of one planet is somehow doubled, the force of gravity between it and a neighboring planet would
doubles.
Which of the following is an example in which you are traveling at constant speed but not at constantvelocity?
driving around in a circle at exactly 100 km/hr
In order to do a negative amount of work you must
exert a force and move opposite to the direction of the force.
The force that accelerates a rocket in outer space is exerted on the rocket by the
exhaust gases.
If you are backing up but slowing down, your acceleration is directed
forwards
Suppose you are standing on a bathroom scale when you are flying in a jet airplane. For a moment the scale reads less than your actual weight. During that moment, it's exerting an upward force on you that is
greater than your weight
A hydraulic device has two pistons, one with a small cross-section area and another piston with alarger cross-section area. If a given force is applied to the small piston, the output force on thelarger-area piston will be
greater.
Suppose you have two containers with liquid in them. One has a density of 760 kg/m3 and the other has a density of 910 kg /m3. If an object floats in one container and sinks in the other, the density of the object
has a value between 760 kg/m3 and 910 kg/m3.
You are taking a shower in your dormitory when someone flushes a toilet nearby. The pressure in the cold water line drops and you find yourself showering in what feels like molten lava. This loss of cold water pressure occurs when the toilet lets cold water flow through the pipes delivering it to the bathroom and the water's speed in those pipes increases. Assuming all the piping to be about on the same level, the cold water's faster motion in the delivery pipes reduces its pressure in the shower head because faster moving water
has less pressure than slower moving water.
Does a 3-meter deep large lake or a 6-meter deep small pond exert more pressure on the bottom of the dam?
he 6-meter deep small pond.
The curves on bicycle racetracks are steeply banked, so that the inner edge of each curve is much lower than its outer edge. This banking tips the support force that the track exerts on the bicycle wheel toward the center of each turn. That center-directed or centripetal force on the bicycle is important because it
helps the bicycle accelerate inward to complete each turn without skidding.
The neighborhood children are playing and one has lost a pocketful of change. As a result they all decide to do a close inspection of the sidewalk. They notice that there are gaps in between the sidewalk filled with a felt - like material. These gaps will prevent
high stress due to thermal expansion.
When you pour honey into a bowl, it flows smoothly. If you did the same with water, it would splash. These different behaviors occur because honey's
high viscosity keeps it flowing smoothly while water's low viscosity allows inertia to break its flow into many separate pieces.
The speed of a bullet fired from a gun will be about the same as the speed of the recoiling gun
if the masses of the bullet and gun are equal.
The change in momentum of an object is equal to the
impulse that acts on it.
If the absolute temperature of an object is tripled, the thermal power radiated by this object (assumingthat its emissivity and size are not affected by the temperature change) will
increase by a factor of 81.
The "strokes", or "cycles" in a four - stroke engine are
induction, compression, power, exhaust
Noise-canceling devices such as jackhammer earphones make use of sound
interference.
On a cold day your feet feel warmer on a rug than on a tile floor because a rug
is a poorer conductor of heat.
If a viscous fluid flows steadily in a pipe, the fluid speed
is least near the pipe wall but increases toward the center.
Compared to planets close to the sun, and based upon Kepler's third law of planetary motion, the length of the year of planets farther out from the sun are
larger
What does the period of a pendulum depend on?
length and gravity
A 30-year-old astronaut goes off on a long-term mission in a spacecraft that travels at speeds close tothat of light. The mission lasts exactly 20 years as measured on Earth. At the end of the mission, theastronaut's age would beA) exactly 30 years.
less than 50 years.
A curve ball in baseball curves because of
lift forces.
An object may have potential energy because of its
location
Low-pitched sounds have
low frequencies and long periods
The density of freshwater is 1 g/cm3 and the density of seawater is 1.03 g/cm3. A ship will float
lower in freshwater than in sea water
What quantities does angular momentum depend upon?
mass and velocity
The center of gravity of an object
may or may not lie inside the object
When a 134-Hz tuning fork and a 144-Hz tuning fork are struck, the beat frequency is
more than 8 Hz.
A fan can be used to circulate air around a room. The pressure at the inlet side of the fan is
more than the pressure at the outlet side.
In a soccer game, someone has kicked the ball so that it is heading right toward your face. You want to slow the ball down with your arm. To execute your plan most effectively you should
move your arm in the direction that the ball is moving.
An important feature of the Carnot cycle is that
no engine can be more efficient than a Carnot engine operating between the same two temperatures.
A pedestrian bridge crosses a street. This bridge is entirely supported by columns from below. A gap at each end of the bridge separates the bridge's surface from the sidewalks leading to the bridge. The width of each gap changes with time. This width is smallest
on hot days.
The vibrations along a transverse wave move in a direction
perpendicular to the wave.
Melting is a ______ that requires energy ________ for the melting system.
phase transition; input
Freezing is a ____________ that requires energy ________ for the melting system.
phase transition; release
Suppose your car's speed doubles. By what factor will its kinetic energy change?
quadruple
By what primary heat transfer mechanism does the sun warm the earth?
radiation
People fighting forest fires carry emergency tents that have shiny aluminum outer surfaces. If there istrouble, a fire fighter can lie under the tent to block the heat from burning trees overhead. The tenthelps because
radiation carries heat downward toward the fire fighter and the aluminum tent reflects most of that radiation
Dimples on a golf ball hit without spin
reduce drag.
If the distance between planets is somehow doubled, the force of gravity between them would
reduces by one quarter.
An ideal gas undergoes expansion without changing it's internal energy. During this process, its entropy
remains unchanged.
When an object is set vibrating by a wave having a frequency that matches the natural frequency of the object, what occurs is
resonance.
A "bouncy" or "lively" ball bounces higher from a rigid, immovable surface than a "dead" ball does because the "bouncy" ball
returns more collision energy as rebound energy
When stringing telephone lines between poles in the summer, it is advisable to allow the lines to
sag.
A motorcycle is
statically unstable and dynamically stable
If you swing a stone overhead in a horizontal circle and the string breaks, the tendency of the stone isto follow a
straight-line path.
For the particular medium, the speed of sound varies with
temperature.
Fluids have viscosity because
the atoms and molecules within the fluid interact with each other, producing internal frictional forces.
When you sit facing a campfire outdoors, your face feelsquite warm because
the campfire is radiating heat towards your skin.
When you drop a rubber ball on the floor and it bounces, the direction of its velocity reverses because
the floor exerts an upward support force on the ball and this force stops the ball's descent and eventually propels it upward.
It is possible for two objects of equal mass to have different moments of inertia about the same axis because
the moment of inertia depends on the total mass and the mass distribution.
When cooking a potato in a conventional oven it is useful to stick a nail in it, which makes it cook faster. This is because
the nail is a good conductor of heat
The acceleration of an object is equal to
the rate of change of its velocity
A ladybug sits at the outer edge of a merry-go-round, and a gentleman bug sits halfway between herand the axis ofrotation. The merry-go-round makes a complete revolution once each second. Thegentleman bug's angular speed is
the same as the ladybug's
Suppose you have an aquarium and you notice that you have a solid plastic decoration and a rock of about the same volume but twice as dense, and both are totally submerged in the water. The buoyant force on the plastic object is about ___________as that on the rock.
the same.
You are watching a semi truck bounce up and down on a spring. At the topmost point in the truck's path,
the truck's velocity is zero but its acceleration is downward.
You are watching a semi truck bounce up and down on a spring. At the topmost point in the truck'spath,
the truck's velocity is zero but its acceleration is downward.
Suppose you push horizontally on the wall of a building. For you to do work on the wall, which of the following need to happen?
the wall moves away from you
You are holding two identical-looking balloons, one filled with air and one filled with water. You drop these two balloons from a very tall bridge and notice that the water-filled balloon hits the ground first because it traveled faster. The object that experienced the larger amount of drag is
the water - filled balloon because it moved faster.
The spin cycle in your washing machine partially dries clothes by spinning them in a perforated metal basket. Such a process works because
the water leaves the basket moving tangent to the circular path
When you ride your scooter you have momentum. When you ride twice as fast you have
twice the momentum.
You open the refrigerator in your room and put in a case of room-temperature root beer. After an hour, the root beer is ice cold. If your room air did not exchange any heat with the outdoor air during that time, the room air will be
warmer because the refrigerator will have pumped heat out of the root beer and into the room air.
A common glass thermometer contains a red or silver liquid that rises upward in a glass tube as the temperature of the thermometer increases. The liquid moves up the tube because
while both the glass and the liquid expand as their temperatures increase, the liquid expands more rapidly than the glass does.
A harmonic oscillator is an oscillator
with a restoring force proportional to its displacement from equilibrium.
Your weight and mass are different in that
your weight depends upon local gravity but your mass does not.