PHYS Practice Exam 1

A book is given a brief shove along a table top and released so that it slides a short distance and comes to rest. According to Aristotle, it stopped because A) its natural motion is to come to rest. B) of its inertia. C) of gravity. D) of friction. E) the ether slows it down to a stop.

A

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

A

An object's "momentum" is defined as A) its mass times its velocity. B) its mass times its speed. C) its weight times its speed. D) its force times its distance. E) its force time is velocity.

A

Falling objects [dropped near the earth's surface, neglecting air resistance] all fall at A) the same constant [or unchanging] acceleration. B) the same constant (or unchanging) speed. C) zero acceleration. D) an acceleration that is larger for more massive objects. E) the same constant [or unchanging] velocity.

A

Which of the following would increase the gravitational force between two objects? A) Moving the two objects closer together. B) Moving the two objects farther apart. C) Reducing the mass of either one of the objects. D) None of these.

A

You are in distant space. A giant boulder, many times larger than you, is at rest in front of you. You tap the boulder lightly with a small hammer. What does the boulder do? A) It accelerates during the tap, up to a slow speed [slower than walking speed], then keeps moving at that speed. B) It speeds up a little during the tap, but after the tap it soon [within a few minutes] slows down and comes to rest. C) It remains at rest. D) It accelerates during the tap, up to a high speed [faster than a fast-moving car], then keeps moving at that speed. E) It accelerates both during and after the tap.

A

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

B

An apple weighing 3 newtons hangs, motionless, from a tree branch. Newton's law of force pairs says that forces always come in pairs. One force acting on the apple is the apple's weight. What is the other force that forms a force pair with the weight? A) The apple pulling downward on the branch. B) The apple pulling upward on Earth. C) Earth pulling downward on the apple. D) The branch pulling upward on the apple.

B

An auto moves at a steady 50 mph down a straight level road. Which of the following is the forward drive force on the auto? A) The drive force is actually zero in this example, because the auto is moving at a constant speed in a straight line. B) The forward push by the road on the tires. C) The backward push by the engine on the car. D) The backward push by the drive tires on the road. E) The forward push by the engine on the car.

B

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

B

Astronauts in orbit around Earth feel weightless because A) there is no gravity out there. B) they are in "free fall" around Earth. C) no forces at all are acting on them. D) they must lose weight for the space program. E) they are moving with constant velocity.

B

Forces of 8 N and 3 N act on an object. If the two forces act in opposite directions, the net force on the object is A) 8 N. B) 5 N. C) 11 N. D) zero. E) impossible to determine

B

Galileo's principle of falling is limited by the condition that A) the two objects must have the same weight. B) air resistance must be negligible. C) Both of the above. D) the two objects must have the same size. E) actually, this principle has no limitations.

B

How strongly, and in what direction, does a 1-newton apple pull on Earth? A) It pulls upward, with a force that is much smaller than 1 newton. B) It pulls upward, with a force of 1 newton. C) It pulls downward, with a force of 1 newton. D) It pulls upward, with a force that is much larger than 1 newton. E) The apple does not pull on Earth at all; it is Earth that pulls downward on the apple.

B

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 backward force on you, opposite to 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 forward force on you, along your direction of motion.

B

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

Is there any actual evidence that our solar system originate from a collapsing cloud of gas, as described in the textbook? A) Evidence comes from observations of Earth's oldest rocks. B) Evidence comes from observations of gas clouds around new stars elsewhere in our galaxy. C) Evidence comes from observations of the moon, meteorites, other planets, and other moons. D) All of the above. E) No, this description is based only on the theory of gravity and other theories.

B

Mary pushes horizontally on a large, heavy table which is standing alone in the middle of a room, and notes that the table does not move despite the fact that she is pushing on it (see the figure). Why doesn't the table move? A) The table pushes back on Mary with a force that is even larger than Mary's pushing force. B) A frictional force is also exerted by the floor on the table, and this force is equal and opposite to the pushing force. C) Very massive objects, such as the table, are difficult to set into motion because of their large inertia. D) The force of gravity pulls downward on the table, and this force cancels the pushing force. E) The table exerts a force on Mary, and this force is equal and opposite to the pushing force.

B

One ancient Greek scientist, Aristarchus, had a theory about the layout of the universe that was quite different from the other Greek theories. According to Aristarchus's theory, A) Earth is at the center and other objects move around Earth in simple circles. B) the sun is at the center and other objects, including Earth, move around the sun in simple circles. C) there is no fixed center anywhere in the universe. D) Earth is at the center, and the planets move around Earth in orbits that could be described as "circles-within-circles" or "loop-the-loops." E) the Earth is held up by Hercules, who stands on a turtle, who stands on an elephant, who stands on Zeus, who is beginning to think that the whole thing isn't worth the effort.

B

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 gravitational force by your body pushing downward on Earth. B) The gravitational force by your body pulling upward on Earth. C) The force by the surface of the seat pushing upward on your body. D) The force by Earth pulling downward on your body. E) The force by your body pushing downward on the seat.

B

The very earliest Greek cosmological theory, several centuries before Ptolemy, stated that A) the entire universe is in reality just the inside of a giant cosmic frog. B) the planets go in simple circles around Earth. C) the planets revolve in loop-the-loops [circles within circles] around Earth. D) the planets revolve in loop-the-loops around the sun. E) the planets go in simple circles around the sun.

B

Which of the following principles explains why guns recoil? A) The law of inertia. B) Conservation of momentum. C) Newton's law of motion. D) Conservation of energy. E) None of the above.

B

Which scientific theory or theories of the atom agrees with all of the atomic experiments performed to date? A) The planetary theory of the atom. B) The quantum theory of the atom. C) The Greek theory of the atom. D) Both the planetary theory and the quantum theory of the atom. E) None of the above theories agree with all of the atomic experiments performed to date.

B

While a rock is falling straight down with negligible air resistance, it has A) a decreasing speed. B) an increasing speed. C) zero speed. D) an unchanging speed. E) None of the above.

B

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 mass would be larger. B) 1 newton on the moon, because then the gold's mass would be larger. C) 1 newton on Earth, because then the gold's weight on Earth would be larger. D) 1 newton on the moon, because then the gold's weight on the moon would be larger. E) It wouldn't make any difference, because the amount of actual gold would be the same in both cases.

B

A primary reason for you to learn science, according to the textbook's opening section, is A) to pass on Western culture to the next generation. B) to increase your intelligence. C) to increase your awareness. D) because a broadly educated person can get a better job. E) Actually there is no good reason all this scientific nonsense.

C

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

C

How did Newton deduce the dependence of the gravitational force on distance? A) By measuring the gravitational attraction between large massive lead spheres in the laboratory. B) By comparing the time it takes Earth to orbit the sun with the time it takes to spin on its axis. C) By calculating the moon's acceleration, and comparing it with the acceleration of a falling object. D) By observing the way that a large gravitational pendulum moved. E) By comparing the accelerations of objects falling to Earth from different heights.

C

Object A has twice as much mass as object B. If you exert the same force on these two objects, how do their accelerations compare? A) Object A has four times as much acceleration as object B. B) Object A has twice as much acceleration as object B. C) Object A has half as much acceleration as object B. D) They both have the same acceleration. E) It is impossible to answer this without further details concerning the composition of the two object.

C

One-third as much net force is exerted on object A as on object B. The two objects have the same mass. How do their accelerations compare? A) Object A has one-sixth as much acceleration as object B. B) Object A has three times as much acceleration as object B. C) Object A has one-third as much acceleration as object B. D) They both have the same acceleration. E) It is impossible to answer this without further information about the two objects.

C

The basic physical principal principle that explains the operation of rocket engines is A) Galileo's principle of falling. B) the atomic hypothesis. C) the law of force pairs. D) the law of inertia. E) Actually, rockets are unexplainable.

C

We now know that Newtonian physics is not valid [i.e., not correct] for A) gases. B) stationary objects. C) very fast-moving objects. D) solid objects. E) Nonsense--Newtonian physics has never been found to be incorrect.

C

You would be richest if your hunk of gold had a mass of one kilogram A) on the moon. B) on Earth. C) Actually it wouldn't make any difference.

C

A "force" could be best described as A) a mystical aura that emanates after midnight from physics laboratories. B) something that a body possesses, that enables it to keep moving. C) something one body does to another body that keeps the second body moving. D) something one body does to another body that can cause the second body to accelerate. E) something that a body possesses, that enables it to do work.

D

Historically, the earliest atomic model to explain electrical phenomena was A) the Hollywood model. B) the quantum model. C) Galileo's model. D) the planetary model. E) the Greek model.

D

Is it possible to prove, for certain, that a scientific theory is true? A) Yes, by means of a single confirmed experiment that verifies the theory. B) Yes, by carrying out a sufficient number of experimental observations. C) Yes, by deducing it logically from other scientific theories that are known to be true. D) No, because it is always possible that a future experiment will disagree with the theory. E) No, because of the experimental error, or uncertainty, that is always present in any experimental result.

D

Jet planes operate by A) sucking in air and blowing it rapidly out the back of the engine by means of propeller blades inside the engine. B) rocket drive [i.e., ejecting heated rocket fuel rapidly out the back end of the engine]. C) ejecting ions out the back end of the engine. D) sucking in air, heating it , and allowing it to expand out the back end of the engine. E) magic.

D

Suppose that we wish to find the "net force" on an automobile, in order to apply Newton's law of motion to the motion of the automobile. As part of the net force, do we need to include "internal frictional forces" due to internal gears, bearings, etc.? A) No, because only the drive force needs to be included. B) Yes, because every internal and external force must be included. C) Yes, because these forces dissipate some of the car's energy. D) No, because only external forces need to be included. E) Yes, because of Newton's law of force pairs.

D

Suppose that you stand, motionless, on the floor. Regarding the force by the floor on your feet, A) as long as you remain motionless, there is no force by the floor on your feet. B) there is an downward force by the floor on your feet, even though you are not accelerating. C) there is a downward force by the floor on your feet, and this force causes you to accelerate downwards. D) there is an upward force by the floor on your feet, even though you are not accelerating. E) there is an upward force by the floor on your feet, and this force causes you to accelerate upwards.

D

The law of gravity was invented by A) Ptolemy. B) Galileo. C) Kepler. D) Newton. E) Copernicus.

D

Which statement illustrates the fact that two different theories can both agree with the same set of observations? A) Nonsense--it is impossible for two different theories to both be correct. B) the Earth-centered circular orbit theory of the early Greeks, and the later theory of Ptolemy C) the theories of Copernicus and Kepler, after Tycho made his observations D) the theories of Ptolemy and Copernicus, before Tycho made his observations E) the theories of Galileo and Kepler

D

You push your 2 kg physics book along a tabletop, pushing it with 10 newtons of force. The frictional force on it is 4 newtons. The book's acceleration is A) 2 m/s2. B) 5 m/s2. C) 0.2 m/s2. D) 3 m/s2. E) zero.

D

A 1 newton apple hangs from a tree branch. The force by the apple on Earth A) cannot be determined from the given information, because the mass of the earth needs to be given. B) is zero. C) is much smaller than 1 newton, but not zero. D) is 1 newton downward. E) is 1 newton upward.

E

Evidence that things are made of atoms comes from A) the observation that we can smell things such as bread from a distance. B) from the observation that, when chemicals combine to form new chemicals, they do so in simple ratios by weight. C) Both of the above answers. D) Brownian motion. E) All of the above answers.

E

Most meteoroids--rocks moving through outer space--have been moving for billions of years. What, if anything, keeps them moving and why? A) According to Newton's law of gravity, nothing is needed to keep them moving. B) According to current theories about the creation of the universe, the big bang keeps them moving. C) According to Newton's law of motion, their own acceleration keeps them moving. D) According to Newton's law of gravity, the force of gravity keeps them moving. E) According to the law of inertia, nothing is needed to keep them moving.

E

There are three types of collapsed, burned-out stars: black holes, white dwarfs, and A) quasars. B) supernova. C) X-ray stars. D) red giants. E) neutron stars.

E

What similarity did Isaac Newton perceive between a falling apple and the moon? A) The velocities of both are directed toward Earth's center. B) Both have accelerations directed toward Earth's center, although the forces on them are in different directions. C) Both have a velocities and accelerations directed toward Earth's center. D) Both have forces on them toward Earth's center, but their accelerations are in different directions. E) Both have forces on them toward Earth's center, and accelerations directed toward Earth's center.

E

You give your physics book a quick push so that it slides along a table top. It soon slides to a stop. How would Aristotle and Galileo interpret this? A) They agree that physics books can make you crazy and it's best not to think about them. B) Both of them say the force of friction slows it to a stop. C) Aristotle says the force of friction slows it to a stop, but Galileo says this is just the natural motion of the book. D) Both of them say that this is just the natural motion of the book. E). Aristotle says this is just the natural motion of the book, but Galileo says the force of friction slows it to a stop.

E

You throw a ball straight upward. While it is moving upward, the net force on the ball is A) directed oppositely to the acceleration. B) in the upward direction. C) zero. D) in the horizontal direction. E) in the downward direction.

E