Physics 107 Exam
A car of mass 2000 kg is accelerating at 2 m/s2 . What is the magnitude of the net (or resultant) force acting on the car? A) 8,000N B) 10,000N C) Zero D) 4,000N E) 16,000N
D
A source of sound is moving directly towards you: you are stationary (see illustration). Which of the following statements about the sound you receive from the source is true? A) Its speed increases because the source is moving towards you, but its frequency is unchanged. B) Its speed is unchanged even though the source is moving towards you, but its frequency decreases. C) Its speed and frequency both increase because the source is moving towards you. D) Its speed is unchanged even though the source is moving towards from you, but its frequency increases. E) Its speed and frequency both decrease because the source is moving
D
An experimental electric car has an acceleration of 6 m/s2 How long will it take in seconds for the car to accelerate from rest (that is, stationary) to 67 miles per hour if 67 miles per hour is equivalent to 30 m/s? A) 6 B) 9 C) 180 D) 5 E) 36
D
An object is observed to be stationary on a desktop. What can be said about the forces acting on the object? A) There can be only one force acting on the object. B) There are no forces of any sort acting on the object. C) The forces acting on the object can be only action forces, not reaction forces. D) Many forces can act on the object, but they add (sum) to a ZERO net or overall force. E) Many forces can act on the object, but they add (sum) to a NON-ZERO net or overall force.
D
An object moves with constant speed in a straight line. Which of the following statements must be true? A) There can be only one force acting on the object. B) There are no forces of any sort acting on the object. C) The forces acting on the object can be only reaction forces, not action forces. D) Many forces can act on the object, but they add (sum) to a ZERO net or overall force. E) Many forces can act on the object, but they add (sum) to a NON-ZERO net or overall force.
D
Even though electric forces are very much stronger than gravitational forces, gravitational forces, not electric forces, can be used to understand and predict the motion of astronomical objects (such as the planets of the Solar System) because: A) the electric forces do not act through a vacuum. B) electric forces have a longer range than gravitational forces. C) electric forces have a shorter range than gravitational forces. D) most large objects are electrically neutral because they contain as much positive as negative charge. E) the ether dilutes the effects of electric forces, as was shown experimentally in the Michelson-Morley experiment.
D
If a body moves in such a way that its momentum is decreasing, then: A) Its potential energy must be increasing in order for energy to be conserved. B) A non-zero net force must be acting on the body in a direction parallel to the direction in which it is moving. C) The sum of all the forces acting on the body is zero. D) A non-zero net force must be acting on the body in the direction opposite to the direction in which it is moving. E) Its kinetic energy must be constant.
D
In doing a calculation about a moving object, you arrive at an expression in which the numerator is a distance in kilometers and the denominator is a speed in meters per second. You know that a distance divided by a speed gives you a time. When the calculation is completed, the result will be: A) a time in seconds, if you divide by 1000. B) a time in minutes, if you multiply by 60. C) a time minutes, if you divide by 60 and then divide by 1000 D) a time in seconds, if you multiply by 1000. E) a time in minutes if you divide by 1000 and then multiply by 60
D
Newton's third law of motion states that to every action there is an equal and opposite reaction. When someone sits on a chair and holds a baseball in his/her hand, the reaction to the weight of the baseball is: A) the contact (normal) force exerted by the hand on the baseball. B) the contact (normal) force exerted by the ball on the hand. C) the contact (normal) force exerted by the chair on the person sitting on it. D) the gravitational force exerted by the ball on the earth E) Zero, because the action/reaction principle does not apply to weight forces
D
Our galaxy and a nearby galaxy M31 (the famous Andromeda nebula) are approaching each other on a collision course. Assuming the mass of each galaxy remains constant during this process, when the distance between the galaxies has decreased by half, the gravitational force they exert on each other will have: A) increased by a factor of 2 B) decreased by a factor of 1/2 C) decreased by a factor of 1/4 D) increased by a factor of 4 E) remained constant because the masses are assumed to be constant
D
The Law of Conservation of Energy is best described as a: A) A highly controversial piece of Federal legislation in the USA. B) A statement that energy can be created out of nothing or destroyed by machines. C) A statement Energy can neither be created nor destroyed and therefore always stays in the same form (kinetic, potential, thermal, etc.). D) A statement that Energy can neither be created nor destroyed; but energy can be transformed from one form to another (kinetic into potential, etc.) E) A controversial and misleading statement made by certain politically motivated scientists that Energy can be created but not destroyed, and this is alleged to be the cause what is known as Global Warming
D
The Mars Rover robotic explorer (see picture) has a mass of about 200 kg. At some time, Mission Control observes that the Mars Rover is moving in a straight line with a certain (definite) kinetic energy and a certain (definite) momentum. A little time later the Mars Rover is observed to be moving in a different direction from that observed earlier but at the SAME speed. Which of the following statements is true (assume the mass of the Mars Rover has not changed)? A) Neither the kinetic energy nor the momentum has changed. B) The kinetic energy has changed but the momentum has not changed. C) Both the momentum and the kinetic energy have changed. D) The momentum has changed but the kinetic energy has not changed. E) None of these statements is true.
D
A force accelerates a body of mass M. The same force applied to a second body produces twice that acceleration. What is the mass of the second body? A) M/3 B) 3M/2 C) 2M D) 3M E) M/2
E
An object moves with increasing speed in a straight line. Which of the following statements must be true? A) There can be only one force acting on the object. B) Many forces can act on the object, but they add (sum) to a ZERO net or overall force. C) The forces acting on the object can be only action forces, not reaction forces D) There are no forces of any sort acting on the object. E) Many forces can act on the object, but they add (sum) to a NON-ZERO net or overall force
E
If a vibrating object has a frequency of 8 cycles per second, what is its period in seconds? A) 1280 B) 1/640 C) 640 D) 8 E) 1/8
E
MASS of an object is best described as: A) The tendency of material objects to spontaneously accelerate. B) The effect of air resistance on a moving object. C) The tendency of material objects to fall vertically downwards when they are dropped. D) The tendency of material objects to maintain their state of motion. E) A quantitative measure of the inertia of an object
E
The diameter of a structure in the human nervous system known as an AXON has a diameter of about is 0.16 x 10-6 meter. This can also be written as: A) 0.0016meter B) 0.0000016meter C) 0.00016meter D) 0.000016meter E) 0.00000016meter
E
The number of ohms in a circuit is a measure of the: A) force exerted on the charges by the battery. B) amount of charge flowing through a wire each second. C) energy supplied by the battery each second. D) the amount of energy given to each charge as it flows through a battery in the circuit. E) resistance to the flow of charge through the circuit.
E
The position time graph of an object is shown on the left. Which of the following is true at any time between 0 seconds and 20 seconds? A) The object is moving with constant speed but not with constant velocity. B) The speed of the object is increasing. C) The acceleration is zero. D) The speed of the object is decreasing and its acceleration is zero. E) The speed of the object is decreasing and its acceleration is NOT zero.
E
The same car of mass 2000 kg is traveling at 30 m/s. What is the magnitude of the net (or resultant) force that must act on the car if it is to stop in 5 seconds? A) 8,000N B) 10,000N C) Zero D) 4,000N E) 12,000N
E
The voltage of the battery is a direct measure of the A) force in Newtons per Coulomb exerted on the charges by the battery. B) amount of charge flowing through the battery each second. C) the amount of electric charge left in the battery. D) resistance offered by the battery to the flow of charge through the circuit. E) energy supplied by the battery to each Coulomb of charge that passes through it.
E
Two identical boxcars (each of mass m = 2000 kg) are traveling along the same track but in opposite directions. One boxcar has a speed of 3 m/s to the right; the other boxcar has a speed of 6m/s to the left. If the cars collide and couple together, what will be the final speed and direction of the pair? A) 1.5 m/s, right B) 9 m/s, left C) 9 m/s, right D) 9 m/s, left E) 1.5 m/s, left
E
Which of the following correctly expresses Einstein's postulates that form the basis of the theory of Special Relativity? A) Absolute motion can be measured but not absolute time. B) Absolute time can be measured but not absolute motion. C) Only absolute motion can be measured using mechanics, but electromagnetism allows us to measure the absolute time scale proposed by Isaac Newton. D) Absolute motion and absolute time can both be measured if mechanics and electromagnetism are combined. E) Absolute motion cannot be measured and the speed of light will be the same when measured by ALL inertial observers, even if they are in motion relative to one another.
E
Which of the following electromagnetic waves has the longest wavelength? A) Ultra-violet light waves B) X-Ray waves C) Yellow light waves D) Infra-red waves E) Radio waves
E
Which of the following is equal to the speed of light, which is 186,000 miles per second, expressed in scientific (exponent) notation? A) 1.86 x 106 B) 1.86 x 102 C) 1.86 x 103 D) 1.86 x 104 E) 1.86 x 10
E
Which of the following is true about frictional forces? (Think about the lecture demo in which a calculator was pushed and slid across the desk; what happened to the kinetic energy?) A) They convert forces into electromagnetic potential energy. B) They cause kinetic energy to be converted into many forms of potential energy. C) They cause an increase kinetic energy. D) They cause kinetic energy to be converted into frictional potential energy only. E) They can cause a decrease in kinetic energy by converting it into heat (thermal energy)
E
A ball is thrown vertically upwards. At the instant when the ball is at its maximum height, its acceleration is zero.
False
A ball is thrown vertically upwards. At the instant when the ball is at its maximum height, the resultant force acting on it is zero.
False
A woman stands on a bathroom scale while riding in an elevator. According to the scale, her weight when the elevator is not moving is 150 pounds. The scale reads less than this value when the elevator is traveling downwards while slowing down.
False
According to Einstein's Special Theory of Relativity, if you were moving at an appreciable fraction of the speed of light, you would notice that your watch (which is moving with you, attached to your wrist) had slowed down relative to some other periodic phenomenon moving with you such as the rate at which your heart is beating.
False
Einstein was first scientist to understand that it is possible to use mechanics to measure the earth's speed relative to the ether.
False
Energy can be created but not destroyed, and this supposedly causes what is known as Global Warming.
False
If an object falls off a cliff, and air resistance can be ignored, then the distance through which the object falls during a later 1-second time interval is always equal to the distance through which it fell during an earlier 1-second time interval.
False
If the pole-vaulter (see picture) were to land on concrete instead of on a cushion, s/he would experience a greater force on impact because her/his change in momentum would be greater
False
Newton's first law of motion (also called the Inertial Law) may be correctly summarized by stating that the effect of a net (or resultant) force acting on a mass is to cause that mass to continue to move at constant speed in a straight line.
False
Speed and velocity mean exactly the same thing when used as technical, scientific terms.
False
The mass of the earth is about 1000 times bigger than the mass of a typical human adult
False
The momentum of an object is a vector that combines the mass and the acceleration of that object
False
The picture on the left illustrates one way in which a wave can be formed on a slinky spring. The waves illustrated in this picture are TRANSVERSE waves.
False
The size of a virus is about 0.005 meters.
False
The unit of electric current is the VOLT
False
What is called KINETIC ENERGY is the name given to energy associated with the position or configuration of an object or system of objects.
False
When a small insect hits the windshield of a moving car, Newton's Third Law tells us that the force exerted by the insect on the car is much less in magnitude than the force exerted by the car on the insect.
False
The Earth is a non-inertial reference system because it spins on its axis, revolves around the sun, and shares the motion of the sun and the galaxy to which the solar system belongs.
True
The Moon experiences a centripetal acceleration towards the Earth.
True
The Newton is the unit of force in the scientific system
True
The order of magnitude of a quantity is its value rounded to the nearest power of 10
True
The scientific unit of time, the second, is defined as the time interval during which a cesium atom makes a certain number of oscillations.
True
The story about Isaac Newton and the falling apple illustrates how Newton realized that though the accelerations of the apple near the surface of the Earth and the Moon in its orbit are different, they are caused by the same force: the gravitational pull of the Earth on the apple and on the Moon.
True
When you apply the brakes in your car and bring the vehicle to rest on a horizontal highway, the kinetic energy of the car is transformed into heat.
True
21. Which of the following statements is NOT true for sound (acoustic) waves? A) They are transverse waves. B) They are generated by oscillating chunks of matter. C) They can travel only through gasses, liquids, and solids. D) They are longitudinal waves. E) They cause periodic variations in the pressure of the medium through which they pass.
A
A racecar is moving counterclockwise on a circular path as shown in the diagram. Imagine that at this instant, the car is at point P and moving at a speed of 100 mph. Imagine that the car hits a large oil slick that reduces the force of friction to zero. In what direction will the car begin to slide? A) ↑ B)→ C) ↓ D) ← E)
A
Einstein's theory of Special Relativity introduces the idea that: A) Observers in relative motion will measure different time intervals between the same pair of events. B) Observers in relative motion always measure the same time interval between the same pair of events. C) Observers in relative motion will measure different values for the speed of light. D) There is an absolute time scale throughout the universe; this time scale is the same for all observers independent of their state of motion. E) Time slows down the faster you move, so if you were travelling at a speed close to the speed of light you would notice that your watch (or other clock) was running slow.
A
Light travels at 3 x 108 meters in every second. At night at this time of the year, you will see a bright white star in the southern sky which is Rigel, in the constellation of Orion. Astronomers tell us that Rigel is about 8.5 x 1015 kilometers from the earth. What is the ORDER OF MAGNITUDE of the time measured in years that it takes for the light from Rigel to reach the earth? A) 103 B) 106 C) 109 D) 10 E) 101
A
An experimental electric car has an acceleration of 6 m/s2. The car is accelerating and speeding up. At some time it is traveling at 13.4 m/s. How fast will it be going 1.5 seconds later? A) 19.4 m/s B) 22.4 m/s C) 24 m/s D) 26.1 m/s E) 20.1 m/s
B
An observer drops a ball in a train traveling along a straight, horizontal track and slowing down (accelerating in the OPPOSITE direction to the motion of the train). What would an observer in the train say about the horizontal force acting on the ball as it falls if s/he applied Newton's Inertial Law (First Law) to the trajectory (motion) of the ball as they observe it? A) There is a horizontal centrifugal force acting on the ball B) A horizontal force acts in the same direction as that in which the train is moving C) A horizontal force acts in the opposite direction to that in which the train is moving D) There is no horizontal force. E) A vertical centrifugal force must be acting on the ball.
B
In a recent lecture, one demonstration experiment included two large coils and a fluorescent light tube. This demonstration showed that: A) A constant magnetic field produces a constant electric current. B) A changing magnetic field can produce an electric field. C) A constant electric field produces a magnetic field. D) Magnetism is another form of light. E) A changing electric field can create a magnetic field.
B
In his theory of Special Relativity, Einstein A) Abandoned the principle of the relativity of motion. B) Reconciled the apparent conflict between the Galilean principle of relativity and Maxwell's equations that predicted the speed of light waves. C) Introduced the "frame of the fixed stars" into physics as an absolute reference system relative to which the speed of light was defined. D) Postulated the existence of an absolute reference system which he called the ether. E) Introduced into science the revolutionary idea that motion itself was relative.
B
20. Which of the following statements about electromagnetic waves is true? A) They are oscillating, parallel electric and magnetic fields travelling through space. B) They are correctly described as longitudinal waves. C) They are oscillating electric and magnetic fields that are perpendicular to each other and both perpendicular to the direction in which the wave is traveling. D) It is possible for some electromagnetic waves to consist ONLY of an oscillating electric field without an accompanying magnetic field. E) It is possible for some electromagnetic waves to consist ONLY of an oscillating magnetic field without an accompanying electric field
C
A 1500 kg car travelling along a straight, horizontal highway has a speed of 30 m/s. A short time later, the same car is traveling IN THE OPPOSITE DIRECTION at the same speed. Which of the following correctly gives the change in the momentum (in kgm/s) and the kinetic energy (in Joules) of the car? A) 9000; 6.75 x105 B) 4500; 0 C) 9000; 0 D) 4500; 6.75 x105 E) 9000; 1.35 x106
C
A foot is about (roughly) the same length as (hint: visualize a meter stick): A) 10 centimeters B) 100 millimeters C) 30 centimeters D) 10 meters E) 15 millimeters
C
A rock is thrown straight up from the earth's surface. Which one of the following statements concerning the net (resultant) force acting on the rock at the top of its path, when it is instantaneously at rest, is true? A) The direction of the net force changes from up to down. B) The net force is instantaneously equal to zero. C) The net force is equal to the weight of the rock. D) The net force is greater than the weight of the rock. E) The net force is less than the weight of the rock, but greater than zero.
C
On the left you can see a diagram of observers in relative motion (you have seen this in class and in the book). Suppose the man standing by the highway has a bright flashlight that emits very short flashes of light at intervals of 0.1 second as measured by the man holding the flashlight. The people in the van have an identical flashlight that flashes at the same rate when the two flashlights are switched on and placed side by side at rest relative to each other. The people in the van and the man standing on the ground are now moving relative to each other at 80% of the speed of light. According to the theory of Special Relativity, both the man standing by the highway AND the people in the van observe that (the correct statement must be true for ALL observers): A) the flashlight moving relative to them flashes at a slower rate than the flashlight that is stationary relative to them. B) because it is moving, the flashlight in the van flashes at a slower rate than the flashlight held by the man C) the flashlights all continue to flash at the same rate. D) because it is moving, the flashlight in the van flashes at a faster rate than the flashlight held by the man. E) the flashlight moving relative to them flashes at a faster rate than the flashlight that is stationary relative to them.
A
The charged particles that can move through the metal wires in the circuit and thus form the current are: A) Electrons B) Charged hydrogen atoms C) Charged metal atoms D) Neutrons E) Protons
A
The function of the battery is to: A) Supply energy to the charges moving round the circuit. B) Supply positive electric charges to the circuit. C) Supply both positive and negative electric charges to the circuit. D) Supply negative electric charges to the circuit. E) Supply metal atoms that can move about and complete the electric circuit
A
The period of the oscillations of the electric charges of cesium atoms that are used in what are known as atomic clocks have a period of 1.09 x 10-10 seconds. The frequency of these oscillations in Giga Hertz (GHz) where 1Ghz= 109 Hz is closest to: A) 9 B) 0.9 C) 0.09 D) 9 x 103 E) 9 x 102
A
Two identical boxcars (each of mass m = 2000 kg) are on the same track. One is stationary and the other is moving at a speed of 6 m/s. If the cars collide and couple together, what will be the speed of the coupled cars immediately after the collision? A) 3 m/s B) 1.5 m/s C) 0 m/s D) 4.5 m/s E) 4 m/s
A
Which of the following statements about the motion of the body is correct? A) As it moves, its speed increases. B) As it moves, the direction in which the object is moving changes. C) As is moves, its speed remains constant. D) As it moves, its speed decreases. E) This graph illustrates an example of unaccelerated motion.
A
Which of the following the most reasonable estimate of the instantaneous velocity of the object at 20 seconds (the tangent to the curve has been drawn for you)? A) +5.2 m/s B) −5.2 m/s C) −10 m/s D) +2.5 m/s E) +10 m/s
A
Which statement about the velocity and speed of the ball is correct? A) After the speed has decreases to zero at exactly 1.5 seconds, it increases again but the velocity has changed direction. B) The velocity reverses direction at 1.5 seconds when the speed is greatest. C) The velocity changes direction at 1.5 seconds but the speed is constant during the 3 seconds shown on the graph. D) The speed changes direction at 1.5 seconds when the velocity is greatest. E) None of A) through D) are correct.
A
You are riding an elevator from your tenth floor apartment to the parking garage in the basement. When the elevator is speeding up while moving downwards the net force acting on you could be: A) less than your weight and directed downward B) equal to your weight and directed upward C) less than your weight and directed upward D) zero E) twice your weight and directed downward
A
In the picture on the left, a ball slides down a frictionless ramp and collides with a spring. In the third (lowest) picture, (c), the ball is at rest and the spring is compressed with 5 Joules of elastic potential energy stored in the spring. When the spring expands again, its elastic potential energy is converted into kinetic energy and the ball will travel to the left with the same speed with which it travelled to the right in picture (b). Which of the following statements is true? A) The total (potential+ kinetic) energy of the system depicted in the picture is NOT conserved because there is no friction, but the momentum is conserved because this is a closed system. B) The total (potential+ kinetic) energy of the system depicted in the picture is conserved because there is no friction, but the momentum is NOT conserved because this cannot be a closed system. C) Neither the total (potential+ kinetic) energy nor the momentum of the system depicted in the picture is conserved. D) Both the total (potential+ kinetic) energy and the momentum of the system depicted in the picture are conserved. E) Because there is no friction, neither the Law of Conservation of Momentum nor the Law of Conservation of Energy applies to this system.
B
The position time graph of an object is shown on the left. Which of the following statements about the resultant (or net) force acting on the object must be true at any time instant between 0 seconds and 20 seconds? A) It is zero B) It is non-zero and in the opposite direction to the motion of the object C) It is non-zero and in the same direction as the motion of the object D) It is non-zero but could be either in the same direction as or in the opposite direction to the motion of the object. E) It is non-zero and changes direction at time 10 seconds from being in the same direction as the motion of the object to being in the opposite direction to the motion of the object.
B
The same 2000-kg car travels at a speed of 20 m/s in a circle. The centripetal force acting on the car has magnitude 16,000 N. What is the radius in meters of the circle in which the car is turning? A) 100 B) 50 C) 200 D) 150 E) 25
B
The wavelength of a wave on a taught rope is 0.5 m and its speed is 2.0 m/s. What is the PERIOD of the wave in seconds? A) 4 B) 0.25 C) 8 D) 0.125 E) 1
B
Which choice is closest to the average speed of the object in the time interval between 0 s and 20 s? A) 7 m/s B) 2.5 m/s C) 4.5 m/s D) 6 m/s E) 3.5 m/s
B
Which of the following statements is true concerning the gravitational attraction you (that is, your body mass) exert(s) on the earth? A) The force is zero because human beings do not exert gravitational forces. B) The force is not zero but it is very much smaller than other everyday forces you experience. C) The force is equal in magnitude to your body weight. D) The force is equal to your weight multiplied by the ratio of the mass of the earth to your body mass. E) The force is equal to your weight multiplied by the ratio of your mass to the mass of the earth.
B
Which of the following statements is true? (Sound means an acoustic wave in the audio range) A) Both sound and light are strongly diffracted by apertures - such as doorways - that are about 3 ft. (1 meter) in width. B) Sound but NOT light is strongly diffracted by apertures - such as doorways - that are about 3 ft. (1 meter) in width. C) Only sound is diffracted by apertures, but light cannot be diffracted by apertures if any width because it does not show wave-like properties. D) Light but NOT sound is strongly diffracted by apertures - such as doorways - that are about 3 ft. (1 meter) in width. E) Neither sound nor light is strongly diffracted by apertures - such as doorways - that are about 3 ft. (1 meter) in width.
B
Which of the following statements was demonstrated in lecture with equipment similar to that in the picture? A) A constant magnetic field produces a constant electric current. B) A changing magnetic field can produce an electric current. C) A constant electric field produces a magnetic field. D) Magnetism is another form of heat. E) A changing electric field can create a magnet
B
A space probe leaves earth and travels into space. Which of the following statements is true as space probe moves away from the earth (assume that apart from the journey in space, the space probe suffers no other physical changes)? A) The space probe's mass increases and its weight decreases as its distance from the center of the earth increases. B) The space probe's mass decreases and its weight remains constant as its distance from the center of the earth increases. C) The space probe's mass remains constant and its weight decreases as its distance from the center of the earth increases. D) The space probe's mass remains constant and its weight increases as its distance from the center of the earth increases. E) The space probe's mass remains constant, but its weight suddenly decreases to zero about 100 miles above the surface of the earth when it reaches the region where all objects become weightless
C
An astronaut fires an object vertically upward from the surface of an atmosphere free planet at an initial speed of 30.0 m/s. The object is observed to be at its highest point exactly six seconds later. What is the magnitude of the acceleration due to gravity on the surface of this planet? A) 4 m/s2 B) Zero C) 5 m/s2 D) 10 m/s2 E) 6 m/s2
C
Assume that you are riding in a windowless vehicle on a perfectly smooth surface. (You can't feel any motion.) Imagine that you have a collection of objects and measuring devices in the room. Which of the following experiments could you do to prove that the room is moving horizontally at a constant velocity? A) Determining an object's mass by applying a net horizontal force. B) Weighing an object and comparing it to its known weight. C) No mechanical experiment performed within the moving vehicle can prove this. D) Determining the force necessary for an object to move in a circle. E) Measuring the acceleration of freely falling mass
C
Complete the following statement: when a nylon rod is rubbed with fur, the nylon rod becomes negatively charged because: A) protons are transferred from the fur to the rod. B) neutrons are transferred from the rod to the fur. C) electrons are transferred from the fur to the rod. D) protons are transferred from the rod to the fur. E) electrons are transferred from the rod to the fur.
C
The electric current expressed in Amps in the connecting wires directly measures the: A) force exerted on the charges by the battery. B) energy supplied by the battery each second. C) rate of flow of electric charge through the wires. D) forces resisting the flow of charge through the circuit. E) the amount of electric charge left in the battery
C
The mass of a carbon atom is about 2 x 10-26kg, and the mass of large wooden table is 120kg. If you assume that the table is made of carbon, which of the following is the most reasonable estimate for the ORDER OF MAGNITUDE of the number of carbon atoms in the table? A) 1025 B) 10-26 C) 1028 D) 1026 E) 1027
C
Two stationary skaters face each other on perfectly smooth, horizontal ice as illustrated. The skaters have different masses. If the skaters now push against each other and separate, which of the following statements is true? A) The magnitude of the momentum change experienced by the skater with the greater mass is smaller than the magnitude of the momentum change experienced by the skater with the smaller mass. B) The magnitude of the momentum change experienced by the skater with the larger mass is bigger than the magnitude of the momentum change experienced by the skater with the smaller mass. C) The magnitude of the momentum change experienced by the skater with the larger mass is equal to the magnitude of the momentum change experienced by the skater with the smaller mass. D) The total kinetic energy of the two skaters remains constant. E) No mechanical work is performed during this process.
C
Which statement about the magnitude of the acceleration of the ball is correct? A) It is greatest at 1.5 seconds B) It is zero at 1.5 seconds. C) It is constant between 0 and 3 seconds while the ball is in flight. D) It steadily increases between 0 and 3 seconds E) It steadily decreases between 0 and 3 seconds.
C
The diagram illustrates a simple bar magnet which has two magnetic poles: this is called a magnetic dipole. An electric dipole is created by two opposite (that is, positive and negative) electric charges. Which of the following statements is true? A) A magnetic dipole can be separated into isolated north and south poles, but electric dipoles cannot be separated into isolated positive and negative charges. B) Both magnetic dipoles and electric dipoles can be separated into isolated magnetic poles and isolated positive and negative charges. C) Neither magnetic dipoles nor electric dipoles can be separated into isolated magnetic poles and isolated positive and negative charges. D) A magnetic dipole cannot be separated into isolated north and south poles, but electric dipoles can be separated into isolated positive and negative charges. E) A magnetic dipole can be separated into isolated north and south poles ONLY in the presence of an oscillating electric dipole, a process known as electromagnetic induction.
D
The diameter of a typical atomic nucleus is approximately 1/1,000,000,000,000,000 meter. This can also be written as: A) 1015 meter B) 10-8 meter C) 10-14 meter D) 10-15 meter E) 10-10 meter
D
Which of the following is correct? A) centi = 102 B) pico = 1012 C) kilo = 10-3 D) nano =10-9 E) mega = 109
D
Which of the following is the most reasonable estimate of the height of a typical human adult? A) 1.8x102 meters B) 1.8x103 centimeters C) 1.8x104 millimeters D) 1.8x103 millimeters E) 1.8x10-4 kilometers
D
Which of the following statements best describes one of the notable achievements of the physicist James Clerk Maxwell? A) He proved mathematically that an absolute time scale exists through the universe. B) He proved mathematically the existence of the ether. C) He showed that electromagnetic waves propagate instantaneously, that is with infinite speed. D) He developed a mathematical theory of electromagnetism that predicted the speed of electromagnetic waves. E) He demonstrated mathematically that time is relative
D
Which of the following statements best describes why scientists in the nineteenth century had difficulty in interpreting what was meant by the speed of light in a vacuum (empty space)? A) Light does not travel at a finite speed: it is transmitted instantaneously from one place to another. B) The speed of light can only be understood when it travels through air and causes the particles of air to oscillate, and light cannot travel through a vacuum. C) The speed of light was unknown until Albert Einstein measured it. D) To interpret the speed of anything, we need to know relative to what that speed is measured. E) The predictions of electromagnetism turned out to be incorrect when compared with reliable experimental data.
D
Which one of the following choices is equivalent to 105.6 mm? A) 1.056×102 m B) 1.056×10-2 m C) 1.056×10-3 m D) 105.6×10-3 m E) 10.56×10-3 m
D
According to Coulomb's Law, reducing the distance between two electrical charges by a factor of ½ would cause the force they exert on each other to increase by a factor of 4.
True
Experimental evidence of the effect called time-dilation in Special Relativity is provided by the distance that unstable particles called Muons are able to travel in the earth's atmosphere before they decay
True
If an object is moving along a line and has a constant acceleration of 2 meters/s2 , this means that the object's speed must change by exactly 4 meters/s in any 2 s time interval.
True
If the momentum of one object changes in a system of many objects that is subject to no net external force, then the momenta of other objects in that system must also change so that the overall momentum change of the complete system is zero.
True
If two observers accelerating with respect to each other try to use Newton's Laws of Motion to describe the forces acting on a third object, then they will in general disagree about the forces acting on that object.
True
Magnetic fields are caused by moving electric charges.
True
