Quiz and Power Point Questions
The vibrations of a longitudinal wave move in a direction A. along the direction of wave travel B. at right angles to the direction of wave travel C. that changes with speed
A. along the direction of wave travel
When a submerged submarine expels water from its ballast tanks, its density A. decreases. B. increases. C. remains the same. D. None of the above.
A. decreases
When a fish expands its air bladder, the density of the fish A. decreases. B. increases. C. remains the same. D. None of the above.
A. decreases.
Compared with a lightweight glider, a heavier glider would have to push air A. downward with greater force. B. downward with the same force. C. downward with less force. D. None of the above.
A. downward with greater force. The force on the air deflected downward must equal the weight of the glider.
When no air resistance acts on a fast-moving baseball, its acceleration is A. downward, g. B. a combination of constant horizontal motion and accelerated downward motion. C. opposite to the force of gravity. D. centripetal.
A. downward, g.
When a sample of 4°C water is cooled, it A. expands. B. contracts. C. remains unchanged. D. Not enough information.
A. expands. Parts of the water will crystallize and occupy more space.
When an elevator accelerates upward, your weight reading on a scale is A. greater B. less C. zero D. the normal weight
A. greater
If the mass of an object is halved, the weight of the object is A. halved. B. twice. C. depends on location. D. None of the above.
A. halved.
The direction of natural processes is from states of A. higher order to lower order B. lower order to higher order C. disorganization to organization D. disorder to equilibrium
A. higher to lower order
Electric potential energy is measured in joules. Electric potential, on the other hand (electric potential energy per charge), is measured A. in volts. B. in watts. C. in amperes. D. also in joules.
A. in volts.
As the skydiver falls faster and faster through the air, air resistance A. increases. B. decreases. C. remains the same. D. Not enough information.
A. increases.
Your locker gets messier each week. In this case, the entropy of your locker is A. increasing. B. decreasing. C. hanging steady. D. nonexistent.
A. increasing.
As a parcel of air is swept upward, its temperature A. is lowered B. is increased C. remains constant under normal rising D. becomes inverted
A. is lowered
Water pressure provided by a water tower is greater if the tower A. is taller B. holds more water C. both A and B D. None of the above
A. is taller. As height increases, the pressure of the water column increases
What is the maximum height to which water can be drunk through a straw?
10.3 m
In a vertical jump of 0.6 m, determine the time one spends moving upward to the maximum point. Then double the time to calculate the "hang time" - the time the jumper's feed are off the ground. Use d = 0.5 gt^2 and g = 10 m/s^2
0.7 s
What is the net force acting on a box being pulled with a 10 N force to the right and 5 N to the left?
5 N to the right (srlsy if u don't know this one there's no help)
A nucleus with an atomic number of 44 and a mass number of 100 must have how many neutrons
56 neutrons
What is the difference between the atomic structure between an amorphous and a crystalline material? What is an example for each?
A crystalline material has its atoms in a regular array, whereas an amorphous material has a random network structure. Crystalline material: clay, Amorphous material: window glass
What is the ideal efficiency of a heat engine that is operating between a hot reservoir at a temperature of 400 K and a cold sink at a temperature of 300 K? A. 1/4 B. 1/2 C. 1/3 D. 3/4
A. 1/4 Carnot efficiency: (T hot - T cold) / T hot (400 - 300) / 400 = 1/4
A certain machine is 30% efficient. This means the machine will convert A. 30% of the energy input to useful work—70% of the energy input will be wasted. B. 70% of the energy input to useful work—30% of the energy input will be wasted. C. Both of the above. D. None of the above.
A. 30% of the energy input to useful work—70% of the energy input will be wasted.
You watch a person chopping wood and note that after the last chop you hear it 1 second later. How far away is the chopper? A. 330 m B. More than 330 m C. Less than 330 m D. There's no way to tell.
A. 330 m Speed in dry air at 0 C is about 330 m/s.
A cart is pushed to the right with a force of 15 N while being pulled to the left with a force of 20 N. The net force on the cart is A. 5 N to the left. B. 5 N to the right. C. 25 N to the left. D. 25 N to the right.
A. 5 N to the left. Two forces are in opposite directions, so they subtract. The direction is determined by the direction of the larger force.
Suppose you are swirling a can around and suddenly decide to pull the rope in halfway; by what factor would the speed of the can change? A. Double B. Four times C. Half D. One-quarter
A. Double Angular momentum = mass x tangential speed x radius Angular Momentum is proportional to radius of the turn. No external torque acts with inward pull, so angular momentum is conserved. Half radius means speed doubles.
Suppose you take a sharper turn than before and halve the radius, by what factor will the centripetal force need to change to prevent skidding? A. Double B. Half C. Four times D.One-quarter E. None of the above
A. Double Because "radius" is in the denominator, when the radius is halved, centripetal force will double.
Which of these is a restatement of the conservation of energy? A. First law of thermodynamics B. Second law of thermodynamics C. Third law of thermodynamics D. Zeroth law of thermodynamics
A. First law of thermodynamics
When a dish falls, will the change in momentum be less if it lands on a carpet than if it lands on a hard floor? (Careful!) A. No, both are the same. B. Yes, less if it lands on the carpet. C. No, less if it lands on a hard floor. D. No, more if it lands on a hard floor.
A. No, both are the same. The momentum becomes zero in both cases, so both change by the same amount. Although the momentum change and impulse are the same, the force is less when the time of momentum change is extended. Be careful to distinguish among force, impulse, and momentum.
For each degree a volume of air at 0 C is cooled, its volume: A. shrinks by 1/273 B. shrinks by 100/273 C. increases by 1/273 D. increases by 100/273
A. Shrinks by 1/273
There is twice as much molecular kinetic energy in 2 liters of boiling water as in 1 liter of boiling water. Which will be the same for both? A. Temperature B. Thermal energy C. Both A and B. D. Neither A nor B.
A. Temperature Average kinetic energy of molecules is the same, which means temperature is the same for both.
Push a cart along a track so twice as much net force acts on it. If the acceleration remains the same, what is a reasonable explanation? A. The mass of the cart doubled when the force doubled. B. The cart experiences a force that it didn't before. C. The track is not level. D. Friction reversed direction.
A. The mass of the cart doubled when the force doubled. Acceleration = net force / mass If force doubles, acceleration will also double, but it does not, so mass must also be doubling to cancel out effects of force doubling.
The flight of a blimp best illustrates A. the principle of Archimedes B. Pascal's principle C. Bernoulli's principle D. Boyle's law
A. The principle of Archimedes
Work is done in lifting a barbell. How much work is done in lifting a barbell that is twice as heavy the same distance? A. Twice as much B. Half as much C. The same D. Depends on the speed of the lift
A. Twice as much This is in accord with work = force x distance. Twice the force for the same distance means twice the work done on the barbell.
Does a car hoisted for repairs in a service station have increased potential energy relative to the floor? A. Yes B. No C. Sometimes D. Not enough information
A. Yes If the car were twice as heavy, its increase in potential energy would be twice as great. p = mgh
Two people of equal mass on slippery ice push off from each other. Will both move at the same speed in opposite directions? A. Yes B. Yes, but only if both push equally C. No D. No, unless acceleration occurs
A. Yes Regardless of how they push, the result is equal-magnitude forces on equal masses, which produces equal accelerations; therefore, there are equal changes in speed.
Must a car with momentum have kinetic energy? A. Yes, due to motion alone B. Yes, when momentum is non-accelerated C. Yes, because speed is a scalar and velocity is a vector quantity D. No
A. Yes, due to motion alone Acceleration, speed being a scalar, and velocity being a vector quantity are irrelevant. Any moving object has both momentum and kinetic energy.
Must a car with momentum have kinetic energy? A. Yes, due to motion alone B. Yes, when motion is non-accelerated C. Yes, because speed is a scalar and velocity is a vector quantity D. No
A. Yes, due to motion alone kinetic energy = (½)mv2 Acceleration, speed being a scalar, and velocity being a vector quantity are irrelevant. Any moving object has both momentum and kinetic energy.
When a satellite travels at a constant speed, the shape of its path is A. a circle. B. an ellipse. C. an oval that is almost elliptical. D. a circle with a square corner, as seen throughout your book.
A. a circle.
When Sanjay pushes a refrigerator across a kitchen floor at an increasing speed, the amount of friction between the refrigerator and the floor is A. less than Sanjay's push. B. equal to Sanjay's push. C. equal and opposite to Sanjay's push. D. more than Sanjay's push.
A. less than Sanjay's push. The increasing speed indicates a net force greater than zero. The refrigerator is not in equilibrium.
When a 20-N falling object encounters 5 N of air resistance, its acceleration of fall is A. less than g. B. more than g. C. g. D. terminated.
A. less than g. Acceleration of a non-free fall is always less than g. Acceleration will actually be (20 N - 5 N)/2 kg = 7.5 m/s^2
The force of gravity between two planets depends on their A. masses and distance between them. B. planetary atmospheres. C. rotational motions. D. All of the above.
A. masses and distance between them. The equation for gravitational force, cites only masses and distances as variables. Rotation and atmospheres are irrelevant. F = G(m1m2 / d^2)
When you toss a projectile sideways, it curves as it falls. It will be an Earth satellite if the curve it makes A. matches the curved surface of Earth. B. results in a straight line. C. spirals out indefinitely. D. None of the above.
A. matches the curved surface of Earth. For an 8-km tangent, Earth curves downward 5 m. Therefore, a projectile traveling horizontally at 8 km/s will fall 5 m in 1s, and follow the curve of Earth.
If you push against a stationary brick wall for several minutes, you do no work A. on the wall. B. at all. C. Both of the above. D. None of the above.
A. on the wall. But you may are working on your muscles, but not on the wall. W = Fd
Slightly tilted wings of airplanes deflect A. oncoming air downward to produce lift. B. oncoming air upward to produce lift. C. Both A and B. D. Neither A nor B.
A. oncoming air downward to produce lift. When a wing diverts air downward, it exerts a downward force on the air. The air simultaneously exerts an upward force on the wing. The vertical component of this upward force is lift. (The horizontal component is drag.)
When you brush your hair and scrape electrons from your hair, the charge of your hair is A. positive. B. negative. C. Both A and B. D. Neither A nor B.
A. positive
When stringing telephone lines between poles in the summer, it is advisable to allow the lines to A. sag. B. be taut. C. be close to the ground. D. allow ample space for birds.
A. sag.
Although physics may appear to be the most difficult compared to chemistry, biology, geology, and astronomy, it is A. the most intuitive and methodical. B. still the hardest! C. the central science, between chemistry and biology. D. simple enough, but only for especially intelligent people.
A. the most intuitive and methodical. Your physics text has fewer terms than biology or chemistry texts. Physics is a much more basic science than other fields.
When air near the ground on a warm day is heated more than the air above, sound tends to bend A. upward B. downward C. at right angles to the ground D. none of the above
A. upward
The speed of a satellite in an elliptical orbit A. varies B. remains constant C. acts at right angles to its motion D. All of the above
A. varies
The speed of a satellite in an elliptical orbit A. varies. B. remains constant. C. acts at right angles to its motion. D. All of the above.
A. varies.
The equilibrium rule, ∑F = 0, applies to A. vector quantities. B. scalar quantities. C. Both of the above. D. None of the above.
A. vector quantities. Vector addition accounts for + and - quantities. So, two vectors in opposite direction can add to zero.
When the string is pulled down slowly, the top string breaks, which best illustrates the A. weight of the ball B. mass of the ball C. volume of the ball D. density of the ball
A. weight of the ball
When the string is pulled down slowly, the top string breaks, which best illustrates the A. weight of the ball. B. mass of the ball. C. volume of the ball. D. density of the ball.
A. weight of the ball. Tension in the top string is the pulling tension plus the weight of the ball, both of which break the top string.
Which of these is not a scientific hypothesis? A. Protons carry an electric charge. B. Undetectable particles are some of nature's secrets. C. Charged particles bend when in a magnetic field. D. All of the above are scientific hypotheses.
B. Undetectable particles are some of nature's secrets. Choices A and C can be disproved by experiments. Choice B has no test for wrongness, so it is not a scientific hypothesis.
A fast-moving car hitting a haystack or a cement wall produces vastly different results. 1. Do both experience the same change in momentum? 2. Do both experience the same impulse? 3. Do both experience the same force? A. Yes for all three B. Yes for 1 and 2 C. No for all three D. No for 1 and 2
B. Yes for 1 and 2 Although stopping the momentum is the same whether done slowly or quickly, the force is vastly different. Be sure to distinguish among momentum, impulse, and force.
Which of these is a scientific hypothesis? A. The Moon is made of green cheese. B. Atomic nuclei are the smallest particles in nature. C. A magnet will pick up a copper penny. D. Cosmic rays cannot penetrate the thickness of your Conceptual Physics textbook.
All are scientific hypotheses! All have tests for proving wrongness, so they pass the test of being a scientific hypothesis.
What is the Octet Rule that governs the formation of ionic bonds?
All elements have an inherent affinity to achieve the state of the noble gases by having eight electrons in their outer orbits
What are isotopes?
Atoms of the same element with different numbers of neutrons and are identified by their mass number
If a 1 cm^3 cube is scaled up to a cube that is 10 cm long on each side, how does the surface area to volume ration change? A. 1/100 of original B. 1/10 of original C. 10 times original D. 100 times original
B. 1/10 of original Surface area to volume ration ~ 1/size If the size of a cube is now 10 times original size, surface to volume ration will be 1/10 of the original
Suppose the potential energy of a drawn bow is 50 joules and the kinetic energy of the shot arrow is 40 joules. Then A. energy is not conserved. B. 10 joules go to warming the bow. C. 10 joules go to warming the target. D. 10 joules are mysteriously missing.
B. 10 joules go to warming the bow. The total energy of the drawn bow, which includes the poised arrow, is 50 joules. The arrow gets 40 joules and the remaining 10 joules warms the bow and also the target.
A 5-kg iron ball and a 10-kg iron ball are dropped from rest. When the free-falling 5-kg ball reaches a speed of 10 m/s, the speed of the free-falling 10-kg ball is A. less than 10 m/s. B. 10 m/s. C. more than 10 m/s. D. undetermined.
B. 10 m/s.
How much power is required to raise a 200 kg crate a vertical distance of 2 m in 4 seconds? Work = Fd, Power = Work/t
B. 1000 W
A soccer player kicks a ball with 1500 N of force. The ball exerts a reaction force against the player's foot of A. somewhat less than 1500 N. B. 1500 N. C. somewhat more than 1500 N. D. None of the above.
B. 1500 N.
A 10 cm long spring extends to 12 cm when 1 kg load is suspended from it. What would be its length if a 3 kg load were suspended from it? A. 14 cm B. 16 cm C. 20 cm D. 24 cm
B. 16 cm
You heat a half-cup of tea and its temperature rises by 4°C. How much will the temperature rise if you add the same amount of heat to a full cup of tea? A. 0°C B. 2°C C. 4°C D. 8°C
B. 2°C
Doubling the equal linear dimensions of an object multiplies its area and volume by: A. 2 and its volume by 4 B. 4 and its volume by 8 C. 8 and its volume by 16 D. none of these
B. 4 and its volume by 8
If a girl releases a ball from the top of a building 100 m tall, 1 second later it will have fallen A. 10 m B. 5 m C. less than 5 m D. none of the above
B. 5 m
If a 50-N person is to fall at terminal speed, the air resistance needed is A. less than 50 N. B. 50 N. C. more than 50 N. D. None of the above.
B. 50 N. Then, ΣF = 0 and acceleration = 0
A hoop and a disk both of mass m and radius r are released from the top of an incline at the same time. Which one will reach the bottom first? A. Hoop B. Disk C. Both together D. Not enough information
B. Disk Hoop has larger rotational inertia, so it will be slower in gaining speed.
Suppose you double the speed at which you round a bend in the curve, by what factor must the centripetal force be changed to prevent you from skidding? A. Double B. Four times C. Half D. One-quarter
B. Four times Centripetal force: (mv^2)/r Because the term for "tangential speed" is squared, if you double the tangential speed, the centripetal force will turn out to be four times.
Consider a heavy and light person jumping together with same-size parachutes from the same altitude. Who will reach the ground first?
B. The heavy person They both have the same drag force (for the same speed). The man (heavier) has a greater downward force than the woman (lighter). The man has to drop farther to receive drag force equal to his downward force, so a greater terminal velocity.
A piston in an airtight pump is withdrawn so that the volume of the air chamber is increased 3 times. What is the change in pressure? A. The pressure is 3 times the original pressure B. The pressure is 1/3 the original pressure C. The pressure doesn't change D. There is not enough information to figure this out
B. The pressure is 1/3 the original pressure
Which of these often changes over time with further study? A. Facts. B. Theories. C. Both of the above. D. Neither of the above.
B. Theories. Either facts are known or not known. They do not change. As we collect new information, we refine our ideas; likewise in science, theories may change over time.
How many forces act on a submerged body at rest in a fluid? A. One—buoyancy B. Two—buoyancy and the force due to gravity C. None—in accord with the equilibrium rule, ΣF = 0 D. None of the above.
B. Two—buoyancy and the force due to gravity
When you buy a water pipe in a hardware store, the water isn't included. When you buy copper wire, electrons A. must be supplied by you, just as water must be supplied for a water pipe. B. are already in the wire. C. may fall out, which is why wires are insulated. D. None of the above.
B. are already in the wire.
The vibrations of a transverse wave move in a direction A. along the direction of wave travel B. at right angles to the direction of wave travel C. that changes with speed
B. at right angles
When lift is greater, the helicopter A. climbs down. B. climbs up. C. hovers in midair. D. None of the above.
B. climbs up.
The strength of a stone arch is due to A. tension between adjacent stones B. compression between adjacent stones C. Both of these D. None of these
B. compression between adjacent stones
When a sample of 0°C water is heated, it first A. expands. B. contracts. C. remains unchanged. D. Not enough information.
B. contracts Water continues to contract until it reaches a temperature of 4°C. With further increase in temperature beyond 4°C, water then expands
As the skydiver continues to fall faster and faster through the air, her acceleration A. increases. B. decreases. C. remains the same. D. Not enough information.
B. decreases.
As the skydiver continues to fall faster and faster through the air, net force A. increases. B. decreases. C. remains the same. D. Not enough information.
B. decreases.
When the force that produces an impulse acts for twice as much time, the impulse is A. not changed. B. doubled. C. quadrupled. D. halved.
B. doubled. Ft = Δ(mv) Fx2t = 2Ft = 2Δ(mv)
When the speed of an object is doubled, its momentum A. remains unchanged in accord with the conservation of momentum. B. doubles. C. quadruples. D. decreases.
B. doubles. Momentum = mass velocity , or, mv
When you stand on two bathroom scales with one foot on each scale and with your weight evenly distributed, each scale will read A. your weight. B. half your weight. C. zero. D. more than your weight.
B. half your weight. You are at rest, so ∑F=0. Forces from both scales add to cancel your weight. The force from each scale is one-half your weight
Freight car A is moving toward identical freight car B that is at rest. When they collide, both freight cars couple together. Compared with the initial speed of freight car A, the speed of the coupled freight cars is: A. the same. B. half. C. twice. D. None of the above.
B. half. After the collision, the mass of the moving freight cars has doubled. Can you see that their speed is half the initial velocity of freight car A?
Reverberations are best heard when you sing in a room with A. carpeted walls. B. hard-surfaced walls. C. open windows. D. None of the above.
B. hard-surfaced walls. Rigid walls better reflect sound energy. Fabric is absorbent, and open windows let sound energy escape from the room.
A cannonball shot from a cannon with a long barrel will emerge with greater speed because the cannonball receives a greater A. average force B. impulse C. Both of above D. None of the above
B. impulse
A cannonball shot from a cannon with a long barrel will emerge with greater speed because the cannonball receives a greater A. average force. B. impulse. C. Both of the above. D. None of the above.
B. impulse. The average force on the cannonball will be the same for a short- or long-barreled cannon. The longer barrel provides for a longer time for the force to act, and therefore, a greater impulse. (The long barrel also provides a longer distance for the force to act, providing greater work and greater kinetic energy to the cannonball by virtue of a greater velocity because mass remains constant.)
When a submarine takes water into its ballast tanks, its density A. decreases B. increases C. remains the same D. None of the above
B. increases
When a fish decreases the size of its air bladder, the density of the fish A. decreases. B. increases. C. remains the same. D. None of the above.
B. increases.
When a fish makes itself less dense, the buoyant force on it A. decreases. B. increases. C. remains the same. D. None of the above.
B. increases.
When a submarine takes water into its ballast tanks, its density A. decreases. B. increases. C. remains the same. D. None of the above.
B. increases.
When an elevator accelerates downward, your weight reading is A. greater. B. less. C. zero. D. the normal weight.
B. less. The support force pressing on you is less, so you weigh less. Question: Would you weigh less in an elevator that moves downward at constant velocity?
When the string is pulled down quickly, the bottom string breaks, which best illustrates the A. weight of the ball B. mass of the ball C. volume of the ball D. density of the ball
B. mass of the ball
When the string is pulled down quickly, the bottom string breaks, which best illustrates the A. weight of the ball. B. mass of the ball. C. volume of the ball. D. density of the ball.
B. mass of the ball. It is the "inertia" of the ball that tends to keep it at rest, resulting in the breaking of the bottom string.
According to Coulomb's law, a pair of particles that are placed twice as far apart will experience forces that are A. half as strong. B. one-quarter as strong. C. twice as strong. D. 4 times as strong.
B. one-quarter as strong.
When a projectile achieves escape speed from Earth, it A. forever leaves Earth's gravitational field. B. outruns the influence of Earth's gravity, but is never beyond it. C. comes to an eventual stop, returning to Earth at some future time. D. All of the above.
B. outruns the influence of Earth's gravity, but is never beyond it.
A bird flies by A. flapping its wings. B. pushing air down so that the air pushes it upward. C. hovering in midair. D. inhaling and exhaling air.
B. pushing air down so that the air pushes it upward.
If the masses of two planets are each somehow doubled, the force of gravity between them A. doubles. B. quadruples. C. reduces by half. D. reduces by one-quarter.
B. quadruples.
Acceleration and velocity are actually A. the same. B. rates but for different quantities. C. the same when direction is not a factor. D. the same when an object is freely falling.
B. rates, but for different quantities. Velocity is the rate at which the position of a moving body changes over time: Δx/t, (where Δx is the change of position or distance traveled in time 't') Acceleration is the rate at which velocity changes over time: Δv/t, (where Δv is the change in velocity in time 't')
A 5-kg iron ball and a 10-kg iron ball are dropped from rest. For negligible air resistance, the acceleration of the heavier ball will be A. less. B. the same. C. more. D. undetermined.
B. the same.
When you stand on one foot instead of two, the force you exert on the floor is A. less. B. the same. C. more. D. None of the above.
B. the same.
You do work when pushing a cart with a constant force. If you push the cart twice as far, then the work you do is A. less than twice as much. B. twice as much. C. more than twice as much. D. zero.
B. twice as much.
Sound refraction depends on the fact that the speed of sound is A. constant, irrespective of medium B. variable, dependent on medium C. proportional to frequency D. inversely proportional to wavelength E. None of the above choices are correct
B. variable, dependent on medium
When you step off a curb, you push the Earth downward. The reaction to this force is A. a slight air resistance. B. nonexistent in this case. C. the Earth pushes you upward. D. None of the above.
C. the Earth pushes you upward.
In an ideal pulley system, a woman lifts a 100-N crate by pulling a rope downward with a force of 25 N. For every 1-meter length of rope she pulls downward, the crate rises A. 50 centimeters. B. 45 centimeters. C. 25 centimeters. D. None of the above.
C. 25 centimeters. Work in = Work out; (Fd)in = (Fd)out. One-fourth of 1 m = 25 cm.
A ladybug sits halfway between the rotational axis and the outer edge of the turntable . When the turntable has a rotational speed of 20 RPM, the bug has a tangential speed of 2 cm/s, what will be the rotational and tangential speeds of her friend who sits at the outer edge? A. 1 cm/s B. 2 cm/s C. 4 cm/s D. 8 cm/s
C. 4 cm/s Tangential speed = rω Rotational speed of both bugs is the same, so if radial distance doubles, tangential speed also doubles. So, tangential speed is 2 cm/s x 2 = 4 cm/s. [v = rω]
At one instant, an object in free fall has a speed of 40 m/s. Its speed 1 second later is A. also 40 m/s. B. 45 m/s. C. 50 m/s. D. None of the above.
C. 50 m/s. We assume the object is falling downward.
What is the source of atmospheric pressure? A. Water vapor in air B. Floating dust particles C. Air column extending up to space D. none of these
C. Air column extending up to space
Consider a high-speed bus colliding head-on with an innocent bug. The force of impact splatters the unfortunate bug over the windshield. Which is greater, the force on the bug or the force on the bus? A. Bug B. Bus C. Both are the same. D. Cannot say
C. Both are the same.
A bowling ball is in equilibrium when it A. is at rest B. moves at a constant velocity in a straight-line path C. Both of the above D. None of the above
C. Both of the above
An automobile is accelerating when it is A. slowing down to a stop B. rounding a curve at a steady speed C. Both of the above D. Neither of the above
C. Both of the above
An automobile is accelerating when it is A. slowing down to a stop. B. rounding a curve at a steady speed. C. Both of the above. D. Neither of the above.
C. Both of the above. Change in speed (increase or decrease) is acceleration, so slowing is acceleration. Change in direction is acceleration (even if speed stays the same), so rounding a curve is acceleration.
The atomic number of an element matches the number of A. protons in the nucleus of an atom. B. electrons in a neutral atom. C. Both of the above. D. None of the above.
C. Both of the above. When the atomic number doesn't match the number of electrons, the atom is an ion.
When you step off a curb, Earth pulls you downward and you pull the earth upward. Why do you not sense Earth moving upward toward you? A. Earth is fixed, so it cannot move. B. Earth can move, but other objects on it prevent it from moving. C. It moves very little, almost imperceptibly. D. None of the above.
C. It moves very little, almost imperceptibly.
Two solid blocks of identical size are submerged in water. One block is lead and the other is aluminum. Upon which is the buoyant force greater? A. On the lead block B. On the aluminum block C. Same on both blocks D. There is not enough information to decide.
C. Same on both blocks The buoyant force depends upon the volume of the block that is submerged. Since both submerged blocks are the same size, they displace the same volume of water. So they have the same buoyant force
Why don't barometers use water instead of mercury? A. Water cannot be used because it does not exert pressure B. Water cannot be used because it sticks to the glass C. Water can be used but the barometer will be too tall D. none of the above
C. Water can be used but the barometer will be too tall
If you weigh yourself in an elevator, you'll weigh more when the elevator A. moves upward. B. moves downward. C. accelerates upward. D. All of the above.
C. accelerates upward. The support provided by the floor of an elevator is the same whether the elevator is at rest or moving at constant velocity. Only accelerated motion affects weight.
You are riding in a van at a steady speed and toss a coin up. Where will the coin land? A. behind you B. ahead of you C. back in your hand D. There is not enough information.
C. back in your hand The coin has inertia. It continues sideways with the van and your hand and lands back in your hand.
Water at 4 C will expand when it is slightly A. cooled B. warmed C. both D. neither
C. both
The atomic number of an element matches the number of A. protons in the nucleus of an atom B. electrons in a neutral atom C. both of the above D. none of the above
C. both of the above
When the air from inside a tube is removed by a vacuum pump A. the feather hits the bottom first, before the coin hits B. the coin hits the bottom first, before the coin hits C. both the coin and feather drop together side-by-side D. Not enough info
C. both the coin and feather drop together side-by-side
If the sun suddenly collapsed to become a black hole, the Earth would A. leave the solar system in a straight line path B. spiral into the black hole C. continue to circle in its usual orbit
C. continue to circle in its usual orbit Newton's equation, F = G(mM/d^2), shows us that the interaction force between the mass of the Earth and the Sun doesn't change. The mass of the Earth doesn't change, and neither does the mass of the Sun even though it is compressed, and the distance from the centers remains unchanged.
The use of inclined planes for Galileo's experiments helped him to A. eliminate the acceleration of free fall. B. discover the concept of energy. C. discover the property called inertia. D. discover the concept of momentum.
C. discover the property called inertia. Note that inertia is a property of matter, not a reason for the behavior of matter.
Consider a cart pushed along a track with a certain force. If the force remains the same while the mass of the cart decreases to half, the acceleration of the cart A. remains relatively the same. B. halves. C. doubles. D. changes unpredictably.
C. doubles. Acceleration = net force / mass Because, mass is in the denominator, acceleration increases as mass decreases. So, if mass is halved, acceleration doubles.
When Sanjay pushes a refrigerator across a kitchen floor at a constant speed, the force of friction between the refrigerator and the floor is A. less than Sanjay's push. B. equal to Sanjay's push. C. equal and opposite to Sanjay's push. D. more than Sanjay's push.
C. equal and opposite to Sanjay's push.
You are pushing a crate at a steady speed in a straight line. If the friction force is 75 N, how much force must you apply? A. more than 75 N B. less than 75 N C. equal to 75 N D. not enough information
C. equal to 75 N The crate is in dynamic equilibrium, so, ∑F = 0. Your applied force balances the force of friction.
When lift equals the weight of a helicopter, the helicopter A. climbs down. B. climbs up. C. hovers in midair. D. None of the above.
C. hovers in midair.
To say that body A has a higher temperature than body B is to say that body A has more A. internal energy. B. mass. C. kinetic energy per particle. D. potential energy.
C. kinetic energy per particle.
When a cannon is fired, the accelerations of the cannon and cannonball are different because the A. forces don't occur at the same time. B. forces, although theoretically the same, in practice are not. C. masses are different. D. ratios of force to mass are the same.
C. masses are different.
When you stand on one foot instead of two, the pressure you exert on the floor is A. less B. the same C. more D. None of the above
C. more
A free-falling object has a speed of 30 m/s at one instant. Exactly 1 s later its speed will be A. the same. B. 35 m/s. C. more than 35 m/s. D. 60 m/s.
C. more than 35 m/s. One second later its speed will be 40 m/s, which is more than 35 m/s.
A job can be done slowly or quickly. Both may require the same amount of work, but different amounts of A. energy B. momentum C. power D. impulse
C. power
A job can be done slowly or quickly. Both may require the same amount of work, but different amounts of A. energy. B. momentum. C. power. D. impulse.
C. power.
The velocity of a typical projectile can be represented by horizontal and vertical components. Assuming negligible air resistance, the horizontal component along the path of the projectile A. increases. B. decreases. C. remains the same. D. Not enough information.
C. remains the same. Since there is no force horizontally, no horizontal acceleration occurs.
The velocity of a typical projectile can be represented by horizontal and vertical components. Assuming negligible air resistance, the horizontal component along the path of the projectile A. increases B. decreases C. remains the same D. not enough info
C. remains the same. The horizontal component of a vertical force is 0
When the elevator cable breaks, the elevator falls freely, so your weight reading is A. greater. B. less. C. zero. D. the normal weight.
C. zero. There is still a downward gravitational force acting on you, but gravity is not felt as weight because there is no support force, so your weight is zero.
If a parcel of dry air initially at 10°C at ground level expands adiabatically while flowing upward alongside a mountain a vertical distance of 5 km, what will its temperature be? A. −10°C B. −20°C C. −40°C D. −50°C
C. −40°C Air cools at the rate of 10°C for every 1 km. So, if it rises 5 km, it will cool: 10°C × 5 = 50°C. So, it will be 50°C cooler than on the ground. Its temp. on the ground was 10°C. So, its temp. at the top will be 10°C - 50°C = −40°C.
How do you determine the Carnot efficiency of a heat engine?
Carnot efficiency: (T hot - T cold) / T hot
If the coin diameter is 1 cm, what will be the distance of the coin from the eye when the coin barely eclipses the moon? Coin Diameter/Coin Distance = Moon Diameter/Moon Distance
Coin diameter/Coin distance = 1/110 Coin distance = 1 x 110 = 110 cm
The average speed of driving 30 km in 1 hour is the same as the average speed of driving A. 30 km in 1/2 hour. B. 30 km in 2 hours. C. 60 km in 1/2 hour. D. 60 km in 2 hours.
D. 60 km in 2 hours Average speed = total distance / time So, average speed = 30 km / 1 h = 30 km/h. Now, if we drive 60 km in 2 hours: Average speed = 60 km / 2 h = 30 km/h
What is the distance covered by a freely falling object starting from rest after 4 s? A. 4 m B. 16 m C. 40 m D. 80 m
D. 80 m Distance = (1/2) x acceleration x time x time So: Distance = (1/2) x 10 m/s2 x 4 s x 4 s So: Distance = 80m
A moving object has A. momentum. B. energy. C. speed. D. All of the above.
D. All of the above.
The force of friction can occur A. with sliding objects. B. in water. C. in air. D. All of the above.
D. All of the above. Friction can also occur for objects at rest. If you push horizontally on your book and it doesn't move, then friction between the book and the table is equal and opposite to your push.
The work done in bringing a moving car to a stop is the constant force of tire friction stopping distance. If the initial speed of the car is doubled, the stopping distance is A. actually less. B. about the same. C. twice. D. None of the above.
D. None of the above. Twice the velocity means four times the kinetic energy and four times the stopping distance.
When heat is added to a system, the amount of heat added can A. increase the temperature B. increase the internal energy C. do external work D. all of these
D. all of these
In a hydraulic device, it is impossible for the A. output piston to move farther than the input piston B. force output to exceed the force input C. output piston's speed to exceed the input piston's speed D. energy output to exceed energy input
D. energy output to exceed energy input
In a hydraulic device, it is impossible for the A. output piston to move farther than the input piston. B. force output to exceed the force input. C. output piston's speed to exceed the input piston's speed. D. energy output to exceed energy input.
D. energy output to exceed energy input.
As a balloon rises higher and higher into the atmosphere, its A. volume decreases B. density increases C. weight increases D. none of the above
D. none of the above
When water is turned on in a shower, the shower curtain moves towards the water. This has to do with A. capillary action B. surface tension C. heat capacity D. pressure of a moving fluid E. none of these
D. pressure of a moving fluid
A person who says, "that's only a theory" likely doesn't know that a scientific theory is a A. guess. B. number of facts. C. hypothesis of sorts. D. vast synthesis of well-tested hypotheses and facts.
D. vast synthesis of well-tested hypotheses and facts. The word "theory" in everyday speech is different than its use in science. In science, only a vast and well-reasoned body of knowledge is a theory. For example, gravitational waves - theorized long ago based on acceptable scientific premises, proved only recently.
Joanne drives her car with a mass of 1000 kg at a speed of 20 m/s. Show that to bring her car to a halt in 10 s road friction must exert a force of 2000 N on the car
From Ft = (delta)mv -> F = (delta)mv / t -> (1000 kg)(20 m/s) / 10 s = 2000N
A solid glass ball weighs 1 newton. One with twice the diameter weighs A. 1 N B. 2 N C. 3 N D. 4 N E. More than 4 N
E. More than 4 N
What is the pitch of sound?
Frequency
What is the difference between ionic and covalent bonds?
Ionic bonds are formed when electron transfer takes place between two atoms to satisfy their octet condition. Covalent bonds, however, share electrons to form strong bonds and satisfy the octet requirement.
What are the four types of atomic bonding in solids?
Ionic, Covalent, Metallic, and Van der Waals (weakest)
The isotope Iron 56 has 26 protons, how many neutrons does the isotope Iron 55 have?
Iron isotope with 26 protons containing 30 neutrons is referred to as Iron 56. Iron isotope with 26 protons containing 29 neutrons is referred to as Iron 55
If the masses of two planets are each somehow doubled, the force of gravity between them A. doubles B. quadruples C. reduces by half D. reduces by one-quarter
Quadruples
Which is more elastic - steel or rubber?
Steel. Steel regains its original shape much better than rubber after the force is removed. Elasticity = stress/strain
The speed of sound varies with
Temperature
If rain drops fall vertically at a velocity of 3 m/s and you are running at 4 m/s, how fast do the rain drops hit your face?
They hit your face with the resultant of the horizontal and vertical components, 5 m/s
Explain wave interference
Wave interference occurs when two or more waves interact with each other because they occur in the same place at the same time
Drop a stone in a quiet pond and the resulting ripples carry no water across the pond. If the waves are not transporting water, what is being transported with the wave which certainly moves with a certain velocity?
Waves transport energy, not matter
Does Archimedes' principle apply to gases and liquids?
Yes
