Physics and Human Affairs test 1

outer space

- no air; still gravity

What is the chemical formula for carbon tetrachloride? (tetra means 4)

CCI4

What is the chemical formula for methane?

CH4

Dualism

Descartes' idea that there are two realities, physical and spiritual. In the physical realm, the real or primary qualities are objective, impersonal phenomena such as the motion of atoms. human sense impressions are considered to be secondary qualities, caused by the primary qualities

Gravitational Collapse

Dispersed matter drawing itself together because of gravity

Special Relativity

Einstein's Theory based on the principle of relativity and the principle of the constancy of light speed. In this theory, time and space are not absolute, and light has the same speed in all non accelerated reference frames. This theory applies only to non accelerated observers, whereas the general theory of relativity applies also to accelerated observers.

General Relativity

Einsteins theory based on the principle of equivalence. In this theory, gravity is a consequence of the warping of space-time by masses. this theory applies to accelerated observers; the special theory of relativity applies only to non accelerated observers

Free fall

Falling that is influenced only by gravity and not by air resistance or other influences. For an object that starts from rest and then falls freely to Earth, speed is proportional to the time, and distance os proportional to the square of the time. These portionalities are also correct for any motion that starts from rest and maintains an unchanging acceleration in a straight line/

"planet earth is pulled toward a falling boulder with just as much acceleration as the boulder has as it moves towards the earth" True or false? Why?

False, the boulder has much larger acceleration than does Earth, because the boulder's mass is much smaller than Earth's mass

How can you tell, from naked- eye observation alone, whether a particular object in the sky is a planet?

Follow its position in the sky for a few weeks. If its position relative to the surrounding stars changes, its a planet.

An astronaut on the moon picks up a large rock. Would it be easier, or harder, or neither for him to pick up the same rock on earth?

Harder because it would weigh more

Measurement

Quantitative observation

In a typical large coal- fed electrical generating plant, a ton of coal is burned every 10 seconds. About how many tons of carbon dioxide enter the atmosphere every hour from such a plant?

Since 1 ton of coal is burned every 10 seconds, about 3 tons of CO2 enters they atmosphere every 10 seconds. In 1 hour, there are 3600 seconds, or 3600/10=360 of these 10-second intervals. So, the number of CO2 entering the atmosphere in 1 hour is roughly 3 X 360= 1080 tons

normal force

The force, perpendicular to a solid surface, that is exerted by any solid surface on any object touching it

net force

The total, overall force on an object. The net force due to two forces acting in the same direction is the sum of the two. The net force due to two forces acting in opposite directions is the difference between the two and acts in the direction of the stronger force.

Would you rather have a hunk of gold whose weight is 1 N on the moon or one whose weight is 1 N on Earth- or wouldn't it make any difference?

You would be better off having a hunk of gold whose weight is 1 N on the moon, because it would be a more massive hunk of gold (containing more gold atoms) than one whose weight is 1 N on Earth.

weightlessness

Your body behaves as though it were removed from the effects of gravity but you are not really weightless

Any rock having a very large mass would necessarily A) be very difficult to accelerate. B) move very slowly. C) have a very large weight. D) All of the above. E) need to go on a diet.

a

mass

a body's mass is its amount of inertia and also its quantity of matter. We find a bodies mass in kilograms by comparing its inertia with the inertia of a standard kilogram placed at rest.

Neutron Star

a compact star a few kilometers in diameter, resembling a giant nucleus made of neutrons. It spins rapidly, sending out radio beeps and light flashes. When massive stars (Precollapse masses of 10 to 20 solar masses) run out of fusion fuel, they explode, and the remaining remnant collapses to become a neutron star

Nuclear Fusion

a nuclear reaction in which two nuclei combine to form a single, larger nucleus. Nuclear energy is released whenever two light nuclei are fused to create a nucleus that is lighter than iron.

chemical compound

a pure substance , such as pure water, that is made up of more than one element

Hypothesis

a reasonable but unconfirmed suggestion

White Dwarf

a stars white hot glow

Model

a theory that can be visualized

newton- the unit

a unit of force. the amount of force that can give a 1 kg mass an acceleration 1m/s^2

kilogram

a unit of mass. The mass (or inertia) of the object known as a standard kilogram. Any object that has the same inertia as the standard kilogram has a mass of 1 kilogram

Since there are some 100 billion stars in a typical galaxy, and since there are at least 100 billion galaxies in the known parts of the universe, how many stars are there in the known universe? (write this number out)

100 billion x 100 billion= (a one followed by 22 zeros)

In each of the following cases is the motion accelerated or not accelerated? a) A rock falling freely for 2m b) A meteoroid that is so far from all planets and stars that gravity is negligible c) An artificial satellite orbiting Earth at a steady 30,000 km/hr d) the moon e) An ice-skater coasting on smooth ice, neglecting friction and air resistance

a) accelerated b) not accelerated c) Accelerated since its moving in a circle d) accelerated, since its moving in a circle e) not accelerated

A 3kg rock rests on the ice. You kick it, briefly exerting a 60 N force. Find the rock's acceleration, assuming that there is no friction. Still assuming no friction, what will be the rock's acceleration after your foot is no longer in contact with the rock? Will the rock have a (non zero) speed at this time?

a= F/m= 60 N/ 3 kg= 20 m/s^2 -After the kick, the acceleration must be zero (the law of inertia) the rock will have a non-zero speed.

Which devices in a car are designed to cause acceleration?

accelerator pedal, brake, steering wheel

free fall

an object whose falling is influenced by gravity alone

Experiment

an observation that is designed and controlled by humans

Force

any external influence that causes a body to accelerate

Black Hole

any object whose matter (mass) has gravitationally collapsed into a single point. Nothing can escape from its vicinity. when very massive stars run out of fuel, they explode, and the remnant collapses to become a black hole. Giant black holes exist at the centers of most galaxies, including ours.

chemical decomposition

any process that changes a single substance into other simple substances

chemical reaction

any rearrangement of molecules into new molecular forms

Distinguish astronomy from astrology

astronomy- the scientific study of the stars and other objects in space astrology- belief that the positions of the stars significantly influence human affairs

Is it possible for an object to accelerate but without changing its speed? A) Yes, for example when a car is halfway up a straight hill [a hill whose slope, or angle with the horizontal, does not change] and moving a an unchanging speed. B) Yes, for example when a car turns a corner while maintaining an unchanging speed. C) Both of the above. D) No, because the word "acceleration" means "speeding up." E) No, because the word "acceleration" means "a change in speed."

b

You hold a 2 newton apple, having a mass of 0.2 kg, at rest in your hand. The net force on the apple is then A) 0.2 kg downward. B) zero. C) 0.2 kg upward. D) 2 newtons downward. E) 2 newtons upward.

b

macroscopic

big enough to be seen by the naked eye

satellite

bodies in orbit around larger astronomical bodies

A defining feature of "pseudoscience" is A) it gives the appearance of being scientific. B) it does not use proper scientific methodology. C) Both of the above. D) it is unusual, or odd. E) All of the above.

c

A stone is lifted and released so that it falls to the ground. According to Galileo, it fell because A) its natural motion is to fall. B) of friction. C) of gravity. D) of its inertia. E) of electrical attraction.

c

According to Newtonian physics, and to the philosophical views usually associated with Newtonian physics, the workings of the physical universe are A) partially pre-determined and partially a matter of chance. B) an anti-American plot. C) completely predetermined, just like the workings of a clock. D) completely a matter of chance. E) predetermined in their overall outlines, but with certain details [such as human decision-making] left to chance or to free will.

c

How many atoms are in the alcohol molecule C2H5OH? A) 4 B) 3 C) 9 D) 11 E) insufficient information is given

c

Is it possible to prove, for certain, that a scientific theory is false? A) Yes, by performing a large number of experiments and finding that the outcomes that dispute the theory outnumber the outcomes that support the theory. B) Yes, by taking a vote among all of the scientists who are experts concerning that theory. C) Yes, by means of a single confirmed experiment that contradicts the theory. D) No, because it is always possible that future experiments will agree with the theory. E) No, because science can never be certain of anything.

c

Suppose that the force of gravity between the sun and Earth suddenly stopped operating. What would happen? A) Earth would fall directly inward, into the sun. B) Earth would stop in its orbit around the sun, and remain motionless at its present position. C) Earth would move straight ahead, in a straight line, rather than orbiting the sun. D) Earth would fly directly outward from the sun. E) Earth would continue orbiting the sun, but objects on Earth would have no weight and would float into space.

c

Suppose we could magically triple the distance between Earth and the moon. This would cause the gravitational force by Earth on the moon to be A) reduced to 1/4 of its former value. B) reduced to 1/3 of its former value. C) reduced to 1/9 of its former value. D) be unchanged. E) increased to three times its former value.

c

The idea that everything is made of small particles is A) false and no longer used by scientists. B) not yet widely accepted. C) a useful theory, but not known for certain. D) a useful idea that is known for certain to be true. E) still only a tentative speculation made by many scientists.

c

While a rock is falling straight down it has A) an unchanging speed and an unchanging velocity. B) a changing speed and a constant velocity. C) a changing speed and a changing velocity. D) an unchanging speed and a changing velocity.

c

Would you be richer if you had a hunk of gold whose weight is 1 newton on the moon, or one whose weight is 1 newton on Earth, and why? A) 1 newton on Earth, because then the gold's weight on Earth would be larger. B) 1 newton on the moon, because then the gold's weight on the moon would be larger. C) 1 newton on the moon, because then the gold's mass would be larger. D) 1 newton on Earth, because then the gold's mass would be larger. E) It wouldn't make any difference, because the amount of actual gold would be the same in both cases.

c

Pseudoscience

claims presented so as to appear scientific even though they lack supporting evidence and plausibility and therefore aren't scientific

nucleus

core of an atom

Compared to the gravitational force on a 1 kg object, the gravitational force on a 2 kg object is A) nine times larger. B) four times larger. C) the same. D) twice as large. E) None of the above.

d

One force acting on your body right now is your weight. Which of the following is the best description of the other member of the "force pair" [of which your weight is one member]? A) The force by the surface of the seat pushing upward on your body. B) The force by Earth pulling downward on your body. C) The force by your body pushing downward on the seat. D) The gravitational force by your body pulling upward on Earth. E) The gravitational force by your body pushing downward on Earth.

d

Today, we know that Newton's "laws" are A) often incorrect when applied to liquids. B) incapable of explaining the motions of the planets. C) in agreement with all known experimental evidence. D) often incorrect when applied to molecular-sized objects. E) no longer useful as scientific principles.

d

Which is lightest in weight? A) oxygen atom B) hydrogen atom C) proton D) electron E) water molecule

d

Which of the following best describes the meaning of "force"? A) A body's force is the tendency of that body to continue moving once it is started moving. B) A force is a change in velocity. C) The force that a body has is the amount of work that the body can do. D) A body exerts a force on another body when the first body causes the second body to accelerate. E) The force of a moving body is the distance the body travels divided by the time it takes to travel that distance.

d

While a stone is falling [neglecting air resistance], A) its speed is changing. B) the direction of its velocity is downward. C) it is accelerated. D) All of the above. E) None of the above.

d

A scientific theory [or scientific principle] could best be described as A) an idea that has been proven by observations of the natural world. B) any mental picture, or idea, about the way that the natural world operates. C) a tentative guess about the way the natural world operates. D) an observed fact or collection of facts about the natural world. E) an idea that explains a large collection of observations of the natural world.

e

Is any force exerted on you when you slow down while moving along a straight line? A) No, no force acts as long as you are slowing down. B) Yes, there is a forward force on you, along your direction of motion. C) Yes, there is a sideways force on you. D) Yes, there is a force on you but it is impossible to state the direction of this force because the question contains insufficient information. E) Yes, there is a backward force on you, opposite to your direction of motion.

e

Meteors in outer space keep moving, rather than slowing down and stopping. This behavior is predicted by A) Newton's law of motion. B) the law of force pairs. C) Galileo's law of falling. D) Aristotle's principle of natural motion. E) the law of inertia.

e

atomic number

each number represents a particular type of atom

newtonian physics

effective ideas about motion, force, and gravity

matter

material substances such as wood, cotton, sausage, ice, water, soil, and gold

One car goes from 0 to 30km/hr. Later, another car goes from 0 to 60 km/hr. Can you say which car had the greater acceleration?

no because you don't know how long each acceleration took

electron

one of the fundamental particles. a point particle having negative charge, about 2000 times less massive than a proton

photosynthesis

putting together by light CO2+H2O+Solar energy = C6H12O6+O2

chemical element

roughly 100 substances that cannot be chemically decomposed

periodic table

similar properties are listed vertically and also list the elements in order of increasing atomic number

friction

slowing down due to the roughness of the incline and ball

atom

smallest particle of a chemical element

velocity

speed and direction

acceleration due to gravity

the acceleration of any freely falling object. On Earth, this is about 10 m/s^2 or more precisely, 9.8m/s^2

What is physics?

the branch of science that studies the most general principles underlying the natural world

thermal motion

the disorganized microscopic motion that is associated with temperature

gravity

the downward pull by Earth on objects in Earth's vicinity; that pull that every material object exerts on every other material object

force of gravity

the downward pull by Earth on objects in Earth's vicinity; the pull that every material object exerts on every other material object

Scientific Process

the dynamic interplay between experience and ideas

air resistance

the resistance to the motion of an object through the air due to the object's collisions with numerous air molecules

molecule

the smallest particle of a compound that still has the characteristics of that compound

inertia

the tendency to maintain its state of motion, whether it is moving or remaining at rest

When a moving bus comes rapidly to a stop, why do the riders who are standing lurch toward the front of the bus?

they lurch forward because of their own inertia- their bodies have a tendency to keep on moving

Microscopic

to small to be seen with the unaided eye, as opposed to macroscopic, or visible to the unaided eye

Theory

well- confirmed framework of ideas that explains what we observe

Symmetry

when an object can be viewed from several perspectives and still look the same

What two reasons does this chapter give for studying science? (ch. 1)

1) expanded awareness 2) to develop social values appropriate to the scientific age

Is any force exerted on you when you speed up along a straight line? When you slow down along a straight line? How do you know?

A force must be exerted on you, both when you speed up and when you slow down, in order to accelerate you. Newton's law of motion says so.

Does Earth's gravity pull more strongly on a block of wood or on a block of iron having the same size?

Iron. They fall equally fast

If you ride on a smooth, fast train at an unchanging speed and throw a baseball upward inside the train, will the baseball then get left behind and come down toward the rear of the car? explain

The baseball keeps up with the train and comes back down in your hand, just as though you were standing still on earth's surface. This is because of the law of inertia. The ball keeps moving forward in the direction with no change in its forward speed, even though you have released the ball. Your throw simply gives the ball an upward (and then downward) motion, on top of the forward motion that the ball had before you threw it.

Supernova

The explosion of a giant star. Supernovae spread the chemical elements into space and so are the source of the elements heavier than helium in our solar system

Observation

The fact gathering process. A measurement is a quantitative observation, and an experiment is a controlled observation.

Science

The observation and theoretical understanding of the natural world

Newtonian World View

The philosophical notions associated with Newtonian physics, especially the mechanical universe and the democratic ideals implied by universal natural laws. key features: Tiny indestructible particles form the fundamental reality; the future is precisely predictable from the past; nature can be understood by analyzing it into simple individual components.

Mechanical universe

The philosophical view, accompanying Newtonian physics, that the clocklike workings of atoms precisely and predictably determine everything else, including the entire future of the universe.

Quantum Physics

The physical theory of the microscopic behavior of matter and radiation

A car collides head- on with a large truck. Which vehicle exerts the stronger force? Which has the larger force exerted on it? Which experiences the larger acceleration?

The two vehicles exert equally strong forces on each other, and the two vehicles feel equally strong forces from the other vehicle. The car experiences the larger acceleration because it has the smaller mass

weight

The weight of an object is the net gravitational force exerted on it by all other objects

Isaac Newton predicted that because of its spinning motion, Earth would bulge out near the equator and be flattened near the poles. In 1735 the French Academy of Sciences sent an expedition to the Arctic to measure the exact shape of Earth. When they returned, reporting the predicted results, the philosopher Voltaire mocked them with the following couplet: To distant and dangerous places you roam. To discover what Newton knew staying at home. Was Voltaire's sarcasm justified? Why or Why not?

Voltaire's sarcasm was not justified. New scientific predictions must be verified by observation, even though they are sometimes predicted by the theory.