PHYS Exam 3
If an object is placed exactly halfway between Earth and the Moon, it would fall toward the
Earth.
On a boat ride, the skipper gives you a life preserver filled with lead pellets. When he sees the skeptical look on your face, he says that you'll experience a greater buoyant force if you fall overboard than your friends who wear Styrofoam-filled preservers.
He is correct.
When the elevator cable breaks, the elevator falls freely, so your weight reading is
zero
As the ball leaves the girl's hand, one second later it will have fallen
5 meters below the dashed line.
A projectile is launched vertically upward at 50 m/s. If air resistance is negligible, its speed upon returning to its starting point is
50 m/s.
The pressure in a stream of water is reduced as the stream speeds up. Can a stream of water from a fire hose actually knock a person off his or her feet?
It can, and is consistent with Bernoulli's principle.
If you measure the distance between two telephone poles with a steel tape on a very hot day, your measured distance will be
a bit short.
When a satellite travels at a constant speed, the shape of its path is
a circle.
You experience weightlessness
all of the above
The quantity of heat that a substance can transfer relates to its
all of the above.
Pour a liter of water at 40°C into a liter of water at 20°C and the final temperature of the two becomes
at or about 30°C.
Which body glows with electromagnetic waves?
both A and B (Sun & Earth)
If the sun were twice as massive
both of these
The conservation of energy applies to satellites in
both of these
An apple pie will be a net emitter of energy when its temperature is
higher than its surroundings.
When water freezes, it expands. This tells us that the density of ice is
less than the density of water.
Compared with the weight of water, the weight of a liter of ice is
less.
One of water's interesting thermal properties is that when heated it takes a relatively
long time in changing temperature.
As a balloon rises higher and higher into the atmosphere, its
none of the above
The force of Earth's gravity on a capsule in space will lessen as it moves farther away. If the capsule moves to twice its distance, the force toward Earth becomes
one-fourth.
According to Newton, when the distance between two interacting objects doubles, the gravitational force is
one-quarter.
When a projectile achieves escape speed from Earth, it
outruns the influence of Earth's gravity, but is never beyond it
The universal gravitational constant, G, which links force to mass and distance, is similar to the familiar constant
pi.
A good heat conductor is
poor insulator
If the masses of two planets are each somehow doubled, the force of gravity between them
quadruples.
The planet Earth loses heat primarily by
radiation
The surface of Earth loses energy to outer space due mostly to
radiation
If a red hot thumbtack is immersed in warm water, the direction of heat flow will be from the
red hot thumbtack to the warm water.
When stringing telephone lines between poles in the summer, it is advisable to allow the lines to
sag.
Two identical blocks of iron are placed in contact, one at 10°C and the other at 20°C. If the cooler block cools to 5°C and the warmer block warms to 25°C, this would violate the
second law of thermodynamics
The higher the temperature of an object, the
shorter the wavelengths it radiates.
The force of gravity acting on you will increase if you
stand on a planet with a shrinking radius
It is commonly thought that a can of beverage will cool faster in the coldest part of a refrigerator. Knowledge of Newton's law of cooling
supports this knowledge
Sun's radiant energy is composed of shorter wavelengths than Earth's due to Sun's greater
surface temperature.
If the Sun collapsed to a black hole, Earth's gravitational attraction to it would be
the same.
When you stand on one foot instead of two, the force you exert on the floor is
the same.
Tomatoes have a higher specific heat capacity than dough. This means that when you bite into a hot pizza
the tomato sauce feels hotter than the dough
Nellie tosses a ball upward at an angle. Assuming no air resistance, which component of velocity changes with time?
the vertical component
How many forces act on a submerged body at rest in a fluid?
two—buoyancy and the force due to gravity
The speed of a satellite in an elliptical orbit
varies
In comparison with other fundamental forces, the universal gravitational constant G indicates that gravity is
very weak
Inside a freely-falling runaway elevator, your
weight is zero
As you sit in class, is there a buoyant force acting on you?
yes, due to displacement of air
When you step on a weighing scale at noon, Earth pulls you downward and the overhead Sun pulls you upward. The reason the Sun's pull doesn't decrease your weight at noon is because
you, the scale, and Earth are in free fall (in orbit) around the Sun.
When you touch a nail stuck in ice, energy flows from
your hand to the ice
A dirigible that hovers in air A) displaces its volume of air. B) displaces its weight of air. C) Both A and B. D) None of the above.
(c) Both A and B.
On which of these blocks submerged in water is the buoyant force greatest? *Hint: look up their densities.
1 kg of aluminum
A ball tossed at an angle of 30° with the horizontal will go as far downrange as one that is tossed at the same speed at an angle of
60 degrees
Entropy is a measure of
Both of the above (messiness & disorder)
When Philadelphia's temperature is 40°F and Miami's temperature is 80°F
Miami is warmer than Philadelphia.
If you hold one end of a metal bar against a piece of ice, the end in your hand will soon become cold. Does cold flow from the ice to your hand?
No
Which has the higher specific heat capacity, water or land?
Water
If you weigh yourself in an elevator, you'll weigh more when the elevator
accelerates upward.
The universal gravitational constant G was first measured
after Newton's time.
The process of boiling
all of the above
Our Moon in Earth orbit travels fastest when it is
closest
The kinetic energy of a planet is maximum when it is
closest to the Sun
Soaring birds and glider pilots can remain aloft for hours without expending power, due to
convection
In a hydraulic device, it is impossible for the
energy output to exceed the energy input
When you touch a hot potato with your finger, energy flows
from the potato to your finger.
According to Newton, the greater the masses of interacting objects, the
greater the gravitational force between them.
When an elevator you're on (with your handy-dandy bathroom scale) accelerates upward, your weight reading on a scale is
greater.
When a fish makes itself less dense, the buoyant force on it
increases.
Aluminum has a higher specific heat capacity than iron. This means that for equal masses of aluminum and iron, the metal that heats more quickly when the same amount of heat is applied is
iron.
When you squeeze a party balloon to 0.8 its volume, the pressure in the balloon
is 1.25 times greater.
The maximum height to which water can be drunk through a straw
is 10.3 m.
When an elevator accelerates downward, your weight reading is
less
The force of gravity between two planets depends on their
masses and distance apart.
When you toss a projectile sideways, it curves as it falls. It will be an Earth satellite if the curve it makes
matches the curved surface of Earth.
When you stand on one foot instead of two, the pressure you exert on the floor is
more.
A ball rolled along a horizontal surface maintains a constant speed because
no horizontal force acts on it.
The velocity of a typical projectile can be represented by horizontal and vertical components. Assuming negligible air resistance, the horizontal component along the path of the projectile
remains the same.
A projectile that is fired vertically from the surface of Earth at 5 km/s will
rise and fall back to Earth's surface.
A hunter on level ground fires a bullet at an angle of 10 degrees below the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first?
the one fired
An object is dropped and freely falls to the ground with acceleration g. If it is thrown upward at an angle instead, neglecting air drag, the acceleration along its path will be
the same.
Dr. Chuck projects a ball horizontally from a lab bench. If the projection speed of the ball were greater, the time in the air would be
the same.
The first law of thermodynamics is a restatement of the conservation of
energy
Which of these has the greatest density?
100 kg of lead
Escape speed from Earth is
11.2 km/s
You heat a half-cup of tea and its temperature rises by 4°C. How much will the temperature rise if you add the same amount of heat to a full cup of tea?
2 degrees C
A ball player wishes to determine pitching speed by throwing a ball horizontally from an elevation 5 m above ground level. The ball lands 20 m downrange. The player's pitching speed is about
20 m/s.
Newton's most celebrated synthesis was and is of
earthly and heavenly laws
Which unit represents the most energy?
Calorie
If Earth's mass decreased to one-half its original mass with no change in radius, then your weight would
decrease to half.
Open spaces in ice crystals contribute to
decreased density
If a pizza radiates more energy than it absorbs, its temperature
decreases
When a submerged submarine expels water from its ballast tanks, its density
decreases
When a fish expands its air bladder, the density of the fish
decreases.
Systems alone tend to move toward
disorder
A cook who measures a specific amount of butter by placing it in a measuring cup with water in it is using the
displacement rule.
If the mass of one planet is somehow doubled, the force of gravity between it and a neighboring planet
doubles.
When no air resistance acts on a fast-moving baseball, its acceleration is
downward, g.
If the mass of Earth somehow increased with no change in radius, your weight would
increase also.
The same quantity of heat is added to different amounts of water in two equal-size containers. The temperature of the smaller amount of water
increases more.
When a fish decreases the size of its air bladder, the density of the fish
increases.
When a submarine takes water into its ballast tanks, its density
increases.
Your locker gets messier each week. In this case, the entropy of your locker is
increasing
On a cold day your feet feel warmer on a rug than on a tile floor because a rug
is a poorer conductor
Water pressure provided by a water tower is greater if the tower
is taller.
To say that body A has a higher temperature than body B is to say that body A has more
kinetic energy per particle.
