Q&A Hero

Q: If Nellie hangs from a horizontal bar that is supported by four vertical ropes, the tension in the ropes A) are each half her weight. B) are each equal to her weight. C) add to equal her weight. D) none of the above

Q: When Nellie Newton hangs by the ends of a rope draped over a large pulley, the tension in each supporting vertical strand is A) half her weight. B) equal to her weight. C) twice her weight. D) none of the above

Q: The resultant of a 40-N force at right angles to a 30-N force is A) 30 N. B) 40 N. C) 50 N. D) greater than 50 N.

Q: A pair of 10-N vectors at right angles to each other has a resultant of about A) 10 N. B) 14 N. C) 20 N. D) none of the above

Q: When a pair of 10-N forces act on a box of candy, the net force on the box is A) zero. B) about 14 N. C) 20 N. D) Any of the above depending on the directions of forces.

Q: A tree stump is pulled northward by a 10-N force at the same time a 25-N force pulls it southward. The resultant force has a magnitude of A) 0 N. B) 15 N. C) 25 N. D) 150 N.

Q: A block pulled to the left with 15 N and to the right with 5 N at the same time experiences a net force of A) 5 N. B) 10 N. C) 15 N. D) 20 N.

Q: Which of the following is a vector quantity? A) area B) volume C) mass D) none of the above

Q: A force is a vector quantity because it has both A) magnitude and direction. B) mass and velocity. C) action and reaction counterparts. D) speed and direction.

Q: When you quickly jerk a cart forward that has a ball resting in the middle, the A) front of the cart hits the ball. B) back of the cart hits the ball. C) neither, for the ball rides along in the middle as the cart moves forward. D) All of the above depending on how quickly the cart is pulled.

Q: Two students engaged in a tug-of-war each pull a rope in opposite directions with a force of 400 N. The net force on the rope is A) zero and rope tension is 400 N. B) zero and rope tension is 800 N. C) 400 N and rope tension is 800 N. D) 400 N and rope tension is also 400 N.

Q: Nellie pulls with a force of 50 N on a horizontal rope tied to a tree at rest. The net force on the rope is A) 50 N and rope tension is 0 N. B) 50 N and rope tension is also 50 N. C) zero and rope tension is 50 N. D) zero and rope tension is also zero.

Q: Tension is actually a force that tends to A) stretch something. B) compress something. C) break something. D) balance something.

Q: Due to inertia, perhaps a railroad train in motion should continue moving indefinitely when its engine is turned off. This is not observed because railroad trains A) aren't massive enough. B) are too heavy. C) ride on straight tracks. D) encounter opposing forces.

Q: While you are standing in the aisle of a bus, the driver suddenly makes a left turn. You lurch to the right due to A) an unbalanced force. B) your tendency to keep moving forward. C) an equilibrium challenge.

Q: A moving van with a stone lightly glued to the midpoint of its ceiling smoothly moves at constant velocity. When the glue gives way, the stone falls and hits the floor A) ahead of the midpoint of the ceiling. B) exactly below the midpoint of the ceiling. C) behind the midpoint of the ceiling. D) none of the above

Q: When a rocket ship gaining speed in outer space runs out of fuel, it A) gains speed for a short time, then slows down to a constant velocity. B) gains speed for a short time, slows down, and eventually stops. C) no longer gains speed.

Q: If your automobile runs out of fuel while driving, the engine stops. You don't come to an abrupt stop due to A) inertia. B) gravity. C) resistance. D) the principle of continuation.

Q: A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is A) zero. B) less than 30 m/s but more than zero. C) about 30 m/s. D) more than 30 m/s.

Q: A roller-coaster ride with 6 passengers takes 3 minutes. Neglecting friction, a similar ride with 12 passengers aboard would take A) 1.5 minutes. B) 3 minutes. C) 6 minutes. D) 18 minutes.

Q: A sheet of paper can be quickly jerked beneath a container of milk without toppling, which best demonstrates A) net force. B) the difference between force and mass. C) inertia.

Q: When you flick a card from beneath a coin that hardly moves, you're illustrating A) inertia. B) equilibrium. C) support force. D) friction.

Q: Which concept is being illustrated when a tablecloth is quickly yanked beneath dishes resting on a table? A) equilibrium B) friction C) support force D) inertia

Q: Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to A) follow a circular path. B) slow down. C) follow a straight-line path. D) stop.

Q: If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in A) a curved path. B) an outward spiral path. C) an inward spiral path. D) a straight-line path.

Q: When no forces act on moving objects their paths are normally A) straight lines. B) circles. C) ellipses. D) all of the above

Q: The amount of force needed to sustain motion of a rock in outer space is A) a force equal to its weight. B) a force less than its weight if friction is absent. C) none of these

Q: A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is A) equal to its weight. B) equal to its weight divided by its mass. C) equal to its mass times its weight. D) none of the above

Q: A hockey puck sliding across the ice finally comes to rest because A) it seeks its proper and natural state. B) of friction. C) that's just the way it is.

Q: Galileo taught us that if you roll a ball along a level surface it will A) soon slow down due to its natural place. B) keep rolling if friction is absent. C) roll as long as its inertia nudges it along. D) soon roll in the opposite direction.

Q: If no external forces act on a moving object, it will A) continue moving at the same speed. B) move slower and slower until it finally stops. C) come to an abrupt halt. D) none of the above

Q: Galileo's interpretation of motion differed from Aristotle's in that Galileo emphasized A) the acceleration of free fall. B) rates of time. C) the role of distance in describing motion. D) none of the above

Q: Galileo's use of inclined planes allowed him to effectively A) slow down the ball's changes in speed. B) reduce the time of the ball's changes in speed. C) eliminate all changes in speed. D) eliminate friction.

Q: Inertia is defined as a A) force. B) property of matter. C) change in motion. D) none of the above

Q: The first scientist to introduce the concept of inertia was A) Aristotle. B) Galileo. C) Newton. D) Copernicus.

Q: The first scientist to be credited for postulating that Earth circled the Sun was A) Aristotle. B) Copernicus. C) Galileo. D) Newton.

Q: Science later greatly advanced when Galileo favored A) philosophical discussions over experiment. B) experiment over philosophical discussions. C) nonmathematical thinking. D) none of the above

Q: The earliest and most influential Greek philosopher was Aristotle, who among many contributions taught that A) the four elements are earth, water, air, and fire. B) all motion is either natural or violent. C) violent motion requires a sustained push or pull. D) all of the above

Q: Which of the following involves passion, talent, and intelligence? A) art B) literature C) music D) science E) all of the above

Q: The most basic of the sciences of physics, chemistry, and biology is A) physics. B) chemistry. C) biology. D) none of the above

Q: Technology is a tool that can A) be socially beneficial. B) be socially harmful when abused. C) lead to a better world. D) all of the above

Q: Science and technology are A) responsible for all the good in the world. B) responsible for all the bad in the world. C) actually one and the same. D) fundamentally different from each other.

Q: A truly educated person is knowledgeable about A) science. B) the arts. C) religion. D) all of the above

Q: Science, art, and religion normally need not contradict one another because A) all three involve different domains. B) choosing the right one means no need to heed the other two. C) choosing religion and art means no need to heed science. D) choosing science means no need to heed religion and art.

Q: Pseudoscience is best characterized as being A) new age. B) an alternate view to be taken seriously. C) fake. D) all of the above

Q: The statement, "There are regions beneath Earth's crust that will always be beyond the reach of scientific investigation" is A) a fact. B) speculation. C) a hypothesis. D) a scientific statement. E) a theory.

Q: For a scientific hypothesis to be valid, there must be a test for proving it A) right. B) wrong. C) conclusively one way or the other.

Q: Which of the following is a scientific statement? A) candy Bon Bons contain no sugar B) there are things we will never know about C) matter is filled with undetectable particles D) there are parts of the universe that will never be discovered by humans E) none of the above

Q: When a dishonest scientist reports false information, he or she A) as in many other professions, will be excused by the scientific community. B) gets no second chance in the scientific community. C) is elevated in the scientific community.

Q: A theory in the field of science is A) an educated guess. B) less than a fact. C) a synthesis of a large body of well-tested knowledge. D) unchangeable.

Q: The synthesis of a large collection of information that contains well-tested and verified hypotheses about certain aspects of the world is known as a scientific A) fact. B) hypothesis. C) law or principle. D) theory. E) none of the above

Q: Facts in the field of science A) are absolute. B) are changeable. C) mean very little. D) are more important than theories.

Q: An educated scientific guess is a A) hypothesis. B) theory. C) either of these D) neither of these

Q: The scientific method is most effective in A) making hypotheses. B) gaining, organizing, and applying new knowledge. C) discovering new things. D) making theories. E) performing experiments.

Q: The safest way to view an image of the Sun is to use A) a telescope. B) binoculars. C) a pinhole. D) colored sunglasses.

Q: A simple method of measuring the distance between the Earth and the Moon is to place in your line of sight to the Moon a A) magnifying glass. B) coin. C) telescope. D) meterstick.

Q: Spots of sunlight on the ground cast through openings between leaves in trees above are actually A) images of the Sun. B) part of a solar eclipse. C) due to refraction of sunlight. D) all of the above

Q: When we see a half Moon in the sky, the lines between Earth, Moon, and Sun A) are equal in length. B) are parallel to one another. C) form a right triangle. D) all of the above

Q: Eratosthenes' measurements of Earth's size involved A) a deep well in Syene. B) a pillar's shadow in Alexandria. C) surveying the distance between Alexandria and Syene. D) all of the above

Q: Eratosthenes first learned about the position of the Sun in mid-summer by A) consulting library information. B) setting up a stick at Syene. C) setting up a stick at Alexandria. D) setting up sticks at both Syene and Alexandria. E) none of the above

Q: When the Sun shines on the Moon, the Moon casts a shadow A) at all times. B) that is tapered. C) that sometimes falls on Earth. D) all of the above

Q: To a fair approximation, Early Greeks knew the A) size of Earth. B) size of the Moon. C) Earth-Moon distance. D) all of the above

Q: Science is a body of knowledge that A) describes order in nature. B) is an ongoing human activity. C) condenses knowledge into testable laws. D) all of the above E) none of the above

Q: A 100-newton sack of potatoes falls from an airplane. As velocity of fall increases, air resistance also increases, and when air resistance equals 100 N, the acceleration of the sack is 1) zero 2) 5 m/s2 3) 10 m/s2 4) 100 m/s2 and the velocity of the sack will be 5) 0 m/s. 6) 5 m/s. 7) 10 m/s. 8) 100 m/s. 9) constant.

Q: Neglecting all types of friction, if two identical sleds, one empty and the other with four heavy passengers, start sliding down a hill together, the heavier sled will get to the bottom 1) before the empty car, 2) after the empty car, 3) at the same time as the empty car, while in the presence of air resistance, the heavier car will get to the bottom 4) before the empty car. 5) after the empty car. 6) at the same time as the empty car.

Q: Figure N-1 When the spool is pulled to the left, it accelerates toward the 1) right, 2) left, which illustrates the fact that 3) for every force there is an equal and opposite reaction force. 4) net force and acceleration act in the same direction.

Q: A person is attracted toward the center of Earth by a gravitational force of 500 N. The force with which Earth is attracted toward the person is 1) 500 N 2) infinitesimally small 3) billions and billions of tons principally because 4) the forces in question make an action/reaction pair. 5) the mass of the person is negligible compared to the mass of Earth. 6) Earth itself weighs billions and billions of tons. 7) of inertia.

Q: You would have the most quantity of gold if it weighed 1 N on the 1) Moon. 2) Earth. 3) planet Jupiter. 4) would be the same on each. This is because 5) on the Moon a greater mass of gold is required for the gravitational force to equal 1 N. 6) weight and mass are directly proportional to each other. 7) gravitational force per mass is greatest on the most massive planet.

Q: A heavy man and a light man parachute together from a high-flying plane. The first to attain zero acceleration will be the 1) light man 2) heavy man 3) both will attain zero acceleration at the same time. because 4) the gravitational force on each man is the same. 5) of the lesser gravitational force acting on the lighter man. 6) air resistance will eventually counterbalance the weights of both men. 7) the lighter man will not have to fall for as long a time before air resistance equals his weight.

Q: In the absence of air resistance, a boulder and a pebble dropped from rest will fall with equal 1) forces of gravity. 2) accelerations. 3) energies. 4) all these. The reason that this quantity is not greater for the boulder than the pebble is that 5) both the boulder and the pebble fall at the same speed. 6) the initial potential energies of each is the same. 7) gravitational force acting on each is the same. 8) the greater gravitational force on the boulder acts on a correspondingly greater mass.

Q: A baseball is thrown straight upward. At the very top of its trajectory its instantaneous velocity is zero and its acceleration is 1) zero. 2) 10 m/s2. 3) between zero and 10 m/s2. 4) none of these. We can better understand this by noting that when it is at its highest point 5) there momentarily is no motion. 6) its rate of change of motion is still 10 m/s2. 7) although its velocity is not changing, its direction is.

Q: A rifle is fired straight downward from a high-altitude balloon. If the bullet leaves the barrel at 100 m/s, then its speed one second later (neglecting air resistance) will be about 1) 10 m/s 2) 100 m/s 3) 105 m/s 4) 110 m/s and its distance below will be about 5) 5 m. 6) 100 m. 7) 105 m. 8) 110 m. 9) 120 m.

Q: If an apple falls a distance of 2 meters in its first second of fall, then 2 meters in its next second of fall, and again 2 meters during its third second of fall, the acceleration of the apple is 1) 0 m/s2. 2) 2 m/s2. 3) 4 m/s2. 4) 10 m/s2. 5) actually, more than 10 m/s2. This is because 6) no change in velocity occurs during fall. 7) the apple increases in distance by 2 meters for each successive second. 8) the average velocity is 1 m/s for each successive second. 9) its weight is counterbalanced by its inertia.

Q: An object drops in free fall. At one instant it is moving at a speed of 50 meters per second. Exactly one second later its speed is about 1) 10 m/s. 2) 50 m/s. 3) 60 m/s. 4) 100 m/s. This is because 5) no net force acts on the object while in its state of free fall. 6) it gains a speed of about 10 m/s for each second of fall. 7) its velocity nearly doubles each second.

Q: An object is dropped from a position of rest. At the end of the first second of free fall it will have traveled about 1) 0 m 2) 5 m 3) 10 m and its velocity will be about 4) 0 m/s. 5) 5 m/s. 6) 10 m/s.

Q: The force required to maintain a body at constant velocity in free space is equal to 1) the mass of the body. 2) zero. 3) the weight of the body. 4) the force required to stop it. 5) none of these. This is in accordance with the law of 6) inertia. 7) action/reaction. 8) gravitation. 9) energy conservation.

Q: The property of objects to resist a change in motion is called 1) friction, 2) velocity, 3) inertia, 4) acceleration, 5) gravity, and it is measured by its 6) speed. 7) velocity. 8) mass. 9) all of these.

Q: Neglecting friction, a ball rolling along a horizontal plane will 1) accelerate indefinitely. 2) roll until the force used to roll it was used up. 3) roll indefinitely at a constant speed. This illustrates 4) the basic principle that a body requires a push or pull to keep it moving. 5) inertia. 6) the law of net force.

Q: If an object is thrown downward from a tall cliff, its acceleration while falling (in the absence of air resistance) will be 1) less than 10 m/s2. 2) 10 m/s2. 3) greater than 10 m/s2. This is evident from the fact that 4) gravitational force depends upon the state of motion of an object. 5) each successive second the speed of the object increases by an additional 10 m/s. 6) the object was not simply dropped but thrown, therefore having an initial acceleration of fall greater than zero.

Q: The speedometer of a car indicates a constant speed of 30 miles per hour. From this we can say that the acceleration of the car is 1) zero. 2) nonzero. 3) can't really say. This is because 4) no net force is acting on the car. 5) any reading (other than zero) on the speedometer indicates acceleration. 6) the car may be changing its direction.