Physical Science Final
The watt, the unit of power, is equal to the
(volt)(ampere)
The velocity of a ball changes from 15 m/s to 5 m/s in 1 second. What is the acceleration of the ball?
-10 m/s^2
Molecular motion in a gas is the minimum possible at
0 K
What is the corresponding wavelength for the Radio distress calls from ships if the frequency is 2182 Hz?
1.4 x 10^5 m
Transform in SI units 14.5 cubic centimenters
1.45 x 10^-5 cubic meters
The current in a 20-ohm electric heater operated at 240 V is
12 A
Transform in SI units 14.8 kilometers
14,800 meters
The current in a 24 W, 12 V light bulb is
2 A
What is the resistance in a 60 W, 12 V light bulb?
2.4 ohms
Transform in SI units 72 kilometers/hour
20 meters/second
A boat whose speed in still water is 40 km/h is moving on a river whose speed can reach a maximum of 15 km/h. The boat's speed relative to the ground is between
25 and 55 km/h
The primary coil of a transformer has 200 turns and its secondary coil has 50 turns, and the current in the secondary coil is 40 A. When a 12 V alternating current is applied to the primary coil of the transformer, the secondary voltage will be
3 V
Find the number of neutrons in each of the following nuclei 6 3 Li, 13 6 C, 31 15 P, 94 40 Zi
3;6;15;40
If the earth were 2 times closer from the sun as it is now, the gravitational force exerted on it by the sun would be
4 times as large as it is now
Two 240 watt light bulbs are connected in parallel across a 120 V power line. The current in each bulb is
4.0 A
The amount of heat needed to raise the temperature of 1 kg of water by 1 degree C is (the specific heat for water is 4180 j/kg degree C
4180 J
The primary coil of a transformer has 200 turns and its secondary coil has 40 turns. If the current in the secondary coil is 25 A, the current in the primary coil is
5 A
Three 12 V batteries cannot be connected to give a voltage for the set of
6 V
The primary coil of a transformer has 200 turns and its secondary coil has 50 turns, and the current in the secondary coil is 40 A. If the power input of the transformer is 60 W, its power output is
60 W
Which atom is an isotope of 8 4 Be
7 4 Be
An electric iron draws a current of 15 A when connected to a 120 V source. Its resistance is
8 ohms
The voltage needed to produce a current of 8 A in a resistance of 12 ohms is
96 V
What role does common sense play in the scientific method?
Common sense can be misleading and is not a valid form of scientific reasoning
What is the buoyancy force which is acting on the Aluminum block with the dimensions 0.2 m / 0.25 m / 0.125 m - which is immersed completely in water (density of water = 1000 kg/m^3)? What is the direction of the force? (Take the gravity acceleration g = 10 m/s^2)
Fb = 62.5 N; downward
Football player A has a mass of 80 kg and develops a speed of 6 m/s; football player B has a mass of 120 kg and a speed of 5 m/s. If they collide which one will prevail?
Football player B
A 20 kg cart starts from rest and reaches a speed of 20 m/s in 5 seconds. Find the magnitude of the force that must be acting on the cart
Force = 80 N
A golf ball and a ping pong ball are dropped in a vacuum chamber. When they have fallen halfway to the bottom, how do their momenta compare?
Golf ball has greater momentum because it has more mass
A golf ball and ping pong ball are dropped in a vacuum chamber. When they have fallen halfway to the bottom, how do their kinetic energies compare?
Golf ball has more kinetic energy because it has more mass
Why is the Ptolemaic model considered incorrect?
It did not agree as well as the Copernican model does with direct observational evidence
What, if anything, would happen to the shape of the earth if it were to rotate even faster on its axis than it does today?
It would be more flattened at the poles, and bulge more at the equator
SI unit for force
N
Which of the following units could be associated with a vector quantity?
Newton
Is an astronaut orbiting in space actually weightless?
No, the astronaut has weight but because he is orbiting his weight is counterbalanced by the centripetal force
Are all waves either longitudinal or transverse? If not, five an example of one that does not.
No. Water waves are circular, and therefore both longitudinal and transverse
Nearly all the mass of an atom is concentrated in the nucleus. Where is its charge located?
Positive charges are in the nucleus, whereas negative charge is in the electron shells surrounding the nucleus
Find the heat needed when temperature of a .25 kg piece of gold is changing from 10 C to 70 C (specific heat for gold is s gold= 129 J/kg C)
Q = 2257.5 J
If white light is incident on a prism, which color travels the fastest?
Red
Which statement best characterizes the nature of science?
Science is a living body of knowledge, not a set of unchanging ideas
According to the physicist Richard Feynman, "Science is the culture of doubt." What does this mean?
Science is a reliable guide to the natural world precisely because it is self-correcting by being open to change in the light of new evidence
When a person drinks a soda through a straw, where does the force come from that causes the soda to move upward?
Sucking on the straw creates a vacuum, lowering the pressure at the top of the liquid in the straw, relative to the atmospheric pressure on the liquid at the bottom of the straw, resulting in a net upward force
A certain quantity of oxygen occupies a volume of 1.5 m^3 at 283 K and ordinary atmospheric pressure (10^5 N/m^2). If the pressure id doubled, but the volume is held constant, find the new temperature
T final = 566 K
A cup of water and a piece of copper of equal mass are both heated with the same amount of energy. What can we say about the temperature change that each feels?
The copper mass has the larger change in temperature
Newton's discovery of the law of gravity was dependent upon
The development of the Copernican system of the solar system
How are the directions of the electric and magnetic fields of an em wave related to each other and to the direction in which the wave is moving?
The electric field, the magnetic field, and the direction of the motion are mutually perpendicular
About how far will sound travel in 1 second?
The length of 3 football fields
A book rests on a table. What is the reaction force to the force the book exerts on the table?
The table pushes back with an equal force in the opposite direction
An empty dump truck coasts with its engine off along a level frictionless road. What happens to the truck's speed if it starts to rain and water collects in it?
The truck slows down because it has more mass, thus conserving momentum
A certain quantity of oxygen occupies a volume of 1.5 m^3 at 283 K and ordinary atmospheric pressure (10^5 N/m^2). If the temperature is increasing to 1698 K, but the pressure is constant, what will be the final volume?
V final = 9 m^3
Under what circumstances does refraction occur?
When it passes at an oblique angle into a medium where the speed is different
Which kind of electromagnetic wave has a wavelength of 1 nm?
X rays
If you were to step out on the surface of Mars (which has an atmospheric pressure that is much smaller than Earth's), what fate would await you?
You would blow up
Why are both a hot and a cold reservoir needed for a heat engine to operate?
a change in energy states always requires a potential difference between two regions, heat flows spontaneously from warmer regions to cooler regions, there must be somewhere for the wasted heat to be dumped
Which would most likely have a downward acceleration greater than g?
a jet plane with engines thrusting in a downward nose dive.
Which of the following statements in not true
a proton in an atom circulates around it nucleus
A hertz (hz) is
a unit of frequency defined as one cycle per second
If air resistance is ignored, objects fall at constant
acceleration
While a car travels around a circular track at constant speed its
acceleration is zero
When an isotope releases gamma radiation the atomic number
and the mass number remain the same
The primary coil of a transformer is connected to a source of alternating current of voltage V. The voltage of the secondary current is
any of the choices, depending on the ratio of turns in the transformer coils.
If you see a lightning flash and then hear the sound of thunder after 9 seconds, how far away are you from the storm? (the speed of sound v = 343 m/s)
around 3 kilometers
A scientific law or theory is valid
as long as it is not contradicted by new experimental findings
If the earth had no atmosphere, what would the color of the sky be during the day?
black
A book is at rest on a tabletop. One student calculates the potential energy as 15 J. Another student calculates the potential energy as 20 J. What statement is correct?
both answers could be correct
Tides are the effect of the gravitational pull of the
both moon and sun on earth
What is the difference between a hypothesis and a law
both of these statements are correct
The total amount of energy in the universe
can not change
When it is hot outside, your body produces sweat on your skin to
carry heat away from your skin through evaporation
Testing the interpretation. New data will test the formulated interpretation. A scientific interpretation is ____ as long as there is no evidence to prove it wrong.
correct
The law of conservation of energy states: Energy cannot be _____ or destroyed, although it can be changed from one form to another
created
The light-year is an astronomical unit for
distance
Kepler modified the Copernican system by showing that the planetary orbits are
ellipses
Electromagnetic waves transport which of the following
energy
You are swimming underwater and want to spear a fish that swims by. Where should you aim in relationship to where the fish appears to be
exactly where it appears to be
Observation and _______. Fact about nature relevant to that specific study are gathered with insistence on accurate and objective data
experiment
The path of a crate dropped from an airplane flying horizontally at a constant speed appears to ______ to someone in the plane and to _______ to someone on the ground.
fall straight down; follow a curve forward and down
Kepler's Second Law predicts that when the earth is nearer the sun it should move faster. Newton's Law of Universal Gravitation predicts that the earth should move _______, because ______.
faster; Fg is inversely related to the radius by a square factor.
A converging lens
focuses a parallel beam of light at the point behind the lens known as the focal point
The law of conservation of momentum states: In the absence of outside ______, the total momentum of a set of objects remains the same no matter how the objects interact with one another
force
A 5 kg cart starts from rest and reaches a speed of 20 m/s in 5 seconds. Find the magnitude of the force that must be acting on the cart
force = 4 N
Molecules are, in general, farthest apart from one other in
gases
Sound waves travel slowest in
gases
A neutral piece of iron
has equal numbers of protons and electrons
The law of gravity
holds everywhere in the universe
Formulating a problem. Scientists will formulate a ________ which is the scope their study
hypothesis
The nucleus of the greatest stability is found in the isotope of the element
iron
According to Maxwell's equations, the speed of electromagnetic waves in empty space
is equal to the speed of light
The speed of a planet in its elliptical orbit around the sun
is the highest when the planet is closest to the sun
235 U goes through a fission process when
it absorbs a neutron and forms an unstable nucleus
SI unit for mass
kg
Interpretation. The interpretation can generate a scientific _______, which tells us what results we can expect with new data, or a scientific ________, which tells us why the results occur
law; theory
You are looking at the bottom of a lake 1.2 m deep from the boat. To you the lake seems to be
less than 1.2 m deep
What is the mass of an Aluminum block (2700 kg/m^3) with the dimensions .2 m / .25 m /.125 m
m = 16.875 kg
A total of 490 j of work is needed to lift a body of unknown mass through a height of 10 meters. What is its mass? What is the power developed by an engine for 10 seconds? (gravity acceleration g = 9.8 m/s^2)
m = 5 kg P = 49 w
A ball of mass m rolling on a smooth surface collides with a stationary ball of mass M. Under what conditions will the first ball m come to a stop while the second ball M moves off? This happens when M and m have the same size, and the mass of ____.
m = M
Si unit for speed
m/s
SI unit for acceleration
m/s^2
Any object that has kinetic energy must be
moving
Which three fuels provide most of the world's energy today?
natural gas, coal, oil
Suppose you push on a heavy table and the table moves in the direction of the force applied. The work done by the friction force is
negative
The rate of radioactive decay is increased by
none of the above
The protons in a nucleus stay together due to the
nuclear force
If the earth were 2 times as far from the sun as it is now, the gravitational force exerted on it by the sun would be
one-fourth times a large as it is now
If the earth's orbit was farther from the sun than it is now,
our year would be longer
In a transverse wave
particles move perpendicular to the direction of the wave
The time it takes a planet to make one complete trip around the sun is called the planet's
period of revolution
An atom that has lost an electron becomes a
positive ion
An object at rest may have
potential energy
Light of which color has the lowest frequency?
red
Which have a higher momentum: a bullet with a mass of 5 g and a speed of 400 m/s or a soccer ball with the mass of 0.5kg and a speed of only 1% of the bullet?
same momentum
The SI unit for time is
second
The magnetic poles of the earth are called geomagnetic poles. Is the north geomagnetic pole a north or south magnetic pole
south magnetic pole, because the north end of a magnet is attracted to it
A magnetic field does not interact with a
stationary electric charge
Alpha particles bounce backwards when fired at a sheet of thin gold foil because
the alpha particles bounce away from the nuclei of the atoms
A softball player hits a "pop up" (where the ball is hit high above the infield). As the ball rises, we know that
the kinetic energy decreases as the potential energy increases
Even if astronauts on the moon did not need to be in enclosed space suits, they could not speak directly to each other but would have to communicate by radio. Why?
the moon has no atmosphere to transmit sound waves, but em waves do not need a medium to propagate, radio waves can be transmitted in a vacuum, whereas sound waves cannot be, sound depends upon pressure pulses in the molecules of a medium to propagate
If an object has an acceleration of zero, which of the following statements is correct?
the net force is zero, the velocity of the object is constant
Who is faster: someone traveling a mile a minute or someone traveling 20 m/s?
the person traveling a mile a minute travels faster
As a ball falls near the surface of the earth, the action force is the pull of the earth's mass on the ball. The reaction force (as used in Newton's third law.) is
the pull of the ball's mass on the earth
A thick copper wire is connected in a circuit to a battery. If the thick wire is removed and replaced by a thinner copper wire of the same length then we know that
the resistance is bigger and the current is smaller
Compared with her mass and weight on the earth, an astronaut on the Moon, where the acceleration of gravity is 1.6 m/s^2, has
the same mass and less weight
According to the Theory of Special Relativity, for which physical quantity will all observers always find the same value?
the speed of light in a vacuum
A 6 V battery is connected in a circuit. If the 6 V battery is replaced by a 12 V battery
twice as many electrons are moved around the circuit in the same amount of time
The rate of fission reactions in a nuclear reactor is controlled by
using a moderator to turn fast neutrons into slow neutrons, adjusting the percentage of fissionable uranium in the core
Would it be more efficient to warm your bed on a cold night with a hot water bottle that contains 1 kg of water at 500 C or with a 1 kg gold bar at 500 C? Why?
water because it holds more internal heat energy than gold at a given temperature
Under what circumstances does an object float in a fluid
when the weight of an object is less than the upward buoyant force, the object floats
Does every moving body possess kinetic energy; and does every stationary body possess potential energy?
yes; no not necessarily