PHY 101: Intro to Physics - Exam 1
What is the test for whether a hypothesis is scientific or not? A hypothesis is scientific if it is possible to prove it wrong, A hypothesis is scientific if it is possible to prove it right, A hypothesis is scientific if it can be written as an equation, A hypothesis is scientific if the appropriate scientific body says it is,
A hypothesis is scientific if it is possible to prove it wrong
A theory in the field of science is: Unchangeable, A synthesis of a large body of well-tested knowledge, An educated guess, Less than a fact,
A synthesis of a large body of well-tested knowledge
Consider the video demonstration that you just watched. Which of the following changes could potentially allow the ball on the straight inclined (yellow) track to win? Ignore air resistance. A. Increase the tilt of the yellow track B. Make the downhill and uphill inclines on the red track less steep, while keeping the total distance traveled by the ball the same C. Increase the mass of the ball on the yellow track D. Decrease the mass of the ball on the red track.
A. Increase the tilt of the yellow track
Once the distance to a remote object is determined via triangulation, one can measure the angular diameter of the object and convert that to an actual diameter. For relatively small angular diameters of a few degrees or less, the corresponding linear diameter can be approximated using the following expression: Diameter = Distance×(Angular Diameter)/(57.3 degrees) The figure illustrates that the diameter of a remote object increases with its distance and its measured angular diameter. Consider the Moon and Sun. Their angular diameters are both equal to about 0.5 degrees. If the Sun is roughly 400 times more distant than the Moon, how much bigger is the Sun's diameter than the Moon's? About 400 times smaller About 800 times bigger About 400 times bigger
About 400 times bigger
A stubborn stump is pulled by a pair of ropes, each with a force of 200 N, but at different angles as shown. From greatest to least, rank the total force from the ropes on the stump (By letter).
B, A, C
In the figure below, label the essential components used to triangulate the distance to the tree located on the opposite side of the river (assume the baseline remains constant). Choices: Baseline, Distance to Object, Right Angle, Angle that Increases with Increasing Distance to Object, Angle that Decreases with Increasing Distance to Object, Label D
Baseline
How can you use the graph of velocity versus time to estimate the acceleration of the ball? By estimating the value of the area under the graph, By estimating the value of the slope of the graph, By estimating the value from the horizontal axis of the graph, By estimating the value from the vertical axis of the graph,
By estimating the value of the slope of the graph
One way to triangulate the distance to many remote objects, such as stars, is to observe the shifts in their location relative to more distant background objects. This apparent shifting of an object's location with respect to the background objects is known as parallax. Parallax is represented in the figure, where the top image shows the parallax shift that is observed along a baseline that runs from one side of Earth to the other. The bottom two images show what the observer sees from opposite sides of Earth. Using triangulation, the distance to the object can be calculated with simple trigonometric relations. Use the figure to determine how the measured parallax changes in the following situation: As the distance to the object increases, parallax: Increases, Decreases, Remains the Same,
Decreases
What two units of measurement are necessary for describing speed? Distance and time, Distance and length, Average speed and distance, Average speed and time,
Distance and time
What is the role of equations in this book? Equations are guides to thinking and show connections between concepts, Equations are interesting side notes about scientific concepts, Equations will be derived to make you understand science, Equations are for plug-and-chug calculations,
Equations are guides to thinking and show connections between concepts
What are the units for force? Force must be measured in pounds and then converted to newtons, Force must first be measured in newtons, then converted to pounds, Force must be measured in newtons; it can never be measured in pounds, Force can be expressed in newtons or pounds,
Force can be expressed in newtons or pounds
An educated scientific guess is A: Hypothesis, Theory, Either of these, Neither of these
Hypothesis
What did Galileo discover about moving bodies and force in his experiments with inclined planes? In the absence of a retarding force, a body will keep moving at a constant speed in a straight line forever, Bodies rolling down an inclined plane slowed down, Bodies rolling up an inclined plane sped up, Bodies rolling down a steep inclined plane starting at a given height rolled up a gently inclined plane to a higher height,
In the absence of a retarding force, a body will keep moving at a constant speed in a straight line forever
One way to triangulate the distance to many remote objects, such as stars, is to observe the shifts in their location relative to more distant background objects. This apparent shifting of an object's location with respect to the background objects is known as parallax. Parallax is represented in the figure, where the top image shows the parallax shift that is observed along a baseline that runs from one side of Earth to the other. The bottom two images show what the observer sees from opposite sides of Earth. Using triangulation, the distance to the object can be calculated with simple trigonometric relations. Use the figure to determine how the measured parallax changes in the following situation: As the size of baseline increases, parallax: Increases, Decreases, Remains the Same,
Increases
You use two rubber bands, side to side first, to hold an object. Then, the bands are pulled apart in their free ends so that they are not vertical anymore. Compare the forces on the bands, in this situation, to the original case, when there was no angle, and the bands are side by side. The tension (forces) in the bands are now: The same as in the original case since they are still holding the same object, Larger than in the original case. If they were the same, they will not have a large enough vertical component, Larger than in the original case. This is because they were pull aside to reach this new configuration, Smaller than in the original case. Separating them releases some of the tension in them, Smaller than in the original case. The horizontal component of the forces is more effective in pulling the weight of the object, Smaller equal or larger. All cases are possible, the answer depends on the exact angle of separation,
Larger than in the original case. If they were the same, they will not have a large enough vertical component
Must people choose between science and religion? No, scientific and religious beliefs are incompatible, Yes, religion and science are completely antithetical, No, there is no contradiction in being scientific and religious in one's thinking, No, religion and science are essentially the same.
No, there is no contradiction in being scientific and religious in one's thinking
What test can you perform to increase the chance in your own mind that you are right about a particular idea? Write a clear explanation of your idea and share it with everyone to gather objections, Write down your own idea as an equation, See if you can state the objections of your opponents to their satisfaction, Read up on the validity of the axioms you assumed when you crafted your idea,
See if you can state the objections of your opponents to their satisfaction
When the Sun was directly overhead in Syene, why wasn't it directly overhead in Alexandria? Gravity bends light, The Sun is a sphere, Syene is in a different time zone than Alexandria, The Earth is a sphere,
The Earth is a sphere
Why did Aristarchus choose the time of a half Moon to make his measurements for calculating the Earth-Sun distance? The Earth, Moon, and Sun formed an obtuse triangle at that time, The Earth, Moon, and Sun formed a straight line at that time, The Earth, Moon, and Sun formed a right triangle at that time, The Earth, Moon, and Sun formed an acute triangle at that time,
The Earth, Moon, and Sun formed a right triangle at that time
Earth, like everything else illuminated by the Sun, casts a shadow. Why does this shadow taper? The Earth is much larger than the Sun, All shadows taper, The Sun is much larger than the Earth, The Earth and the Sun are the same size,
The Sun is much larger than the Earth
If the distance from the pinhole to the projection surface is doubled, what happens to the area of the illuminated region? The area is now four times as large, The area doubles in size, The area is 3.14 times as large, The area remains the same, The area is one quarter as large, The area is half as large,
The area is now four times as large
What is the net force on an object in either static or dynamic equilibrium? The net force is vertical for static equilibrium and horizontal for dynamic equilibrium, The net force is zero for static equilibrium and greater than zero for dynamic equilibrium, The net force is zero, The net force is equal and opposite to the weight of the object,
The net force is zero
What is the net force on a bag pulled down by gravity with a force of 18 newtons and pulled upward by a rope with a force of 18 newtons? The net force is 36 newtons, The net force is 25 newtons, The net force is zero newtons, The net force is 18 newtons,
The net force is zero newtons
What can you correctly say about a pair of vectors that add together to equal zero? The vectors are equal in magnitude, and have the same direction, The vectors are equal in magnitude, and are opposite in direction, The vectors are not equal in magnitude, and have the same direction, The vectors are not equal in magnitude, and are opposite in direction,
The vectors are equal in magnitude, and are opposite in direction
Lucy Lightfoot stands with one foot on one bathroom scale and her other foot on a second bathroom scale. Each scale reads 365 N. What is Lucy's weight (W)?
W = 730 N
Select the correct equations that show that the acceleration of a hamster is 5 m/s^2 when it increases its velocity from rest to 10 m/s in 2 s. [Acceleration is equal to (Change in Velocity)/(Change in Time)]
a = [10 m/s] / [2 s]
What is the diameter of the Sun measured in Earth diameters? Answers are rounded up to one significant digit. 1000 Earth diameters, 500 Earth diameters, 2000 Earth diameters, 100 Earth diameters, 200 Earth diameters, 50 Earth diameters, 20 Earth diameters, 10 Earth diameters, 10000 Earth diameters, 5000 Earth diameters,
100 Earth diameters
What is the distance between Earth to the Sun measured in Sun diameters? Answers are rounded up to one significant digit. 10 Sun diameters, 20 Sun diameters, 5000 Sun diameters, 500 Sun diameters, 50 Sun diameters, 10000 Sun diameters, 1000 Sun diameters, 2000 Sun diameter, 100 Sun diameters, 200 Sun diameters,
100 Sun diameters
In the experiment you used objects with masses that were not necessarily known. Assume that it is determined that the mass of an object that produces a deformation of size 3, is 120 grams. What is the mass of an object that would produce 1 unit of deformation? 20 grams, 25 grams, 30 grams, 35 grams, 40 grams, 45 grams, 50 grams, 60 grams,
40 grams
Assume that the lamp used in the experiment emits light from a surface of diameter 10 cm and that is located at 1 m. from the pinhole. If the pinhole is 0.5m from the projection surface, what is the diameter of the illuminated region? 2 cm, 10 cm, 2.5 cm, 6.6 cm, 5 cm, 0.5 cm, 3.3 cm, 1 cm,
5 cm
Three pucks, A, B, and C, are shown sliding across ice at the noted speeds. Air and ice friction forces are negligible. Rank them, from greatest to least, by the force needed to keep them moving.
A = B = C
Why do we say that force is a vector quantity? A force has a magnitude and a direction, A force is measured in pounds, and pounds are a vector quantity, A force is a scalar quantity, A force has a magnitude, but not a direction,
A force has a magnitude and a direction
Select a correct description of what a force is along with a correct statement of their properties. Forces are vectors associated to objects, A force is a pull or a push on an object that can be described as a vector, A force is push on an object that can be described as a vector, A force is a vector that can be localized at the position of an object, A force is an action capable to produce acceleration on an object, A force is an energy transfer between objects that can be described as a vector,
A force is a pull or a push on an object that can be described as a vector
In daily life, we see many cases of people who are caught misrepresenting things and who soon thereafter are excused and accepted by their contemporaries. How is this different in science? A scientist who lies in a scientific publication will suffer professional excommunication, A scientist who proposes a hypothesis that is eventually disproven is never allowed to be a scientist again, A scientist who disagrees with current theory is never allowed to be a scientist again, A scientist who makes a mistake is never allowed to be a scientist again,
A scientist who lies in a scientific publication will suffer professional excommunication
Briefly, what is science? Science describes the order in nature and the causes of that order, Science is a way of knowing about the world and making sense of it, Science creates testable laws and theories, All of the above,
All of the above
Eratosthenes' measurements of Earth's size involved: A pillar's shadow in Alexandria, A deep well in Syene, Surveying the distance between Alexandria and Syene, All of the above,
All of the above
What exactly is meant by a "freely falling" object? An object in free fall falls under gravity in air with air resistance but no other resistance An object in free fall falls with constant speed An object in free fall falls with constant velocity An object in free fall falls under gravity alone with no friction
An object in free fall falls under gravity in air with air resistance but no other resistance
What does it mean to say something is in mechanical equilibrium? An object in mechanical equilibrium must experience no forces, An object in mechanical equilibrium experiences a zero net force, An object in mechanical equilibrium is always in motion, An object in mechanical equilibrium experiences a net force twice its weight,
An object in mechanical equilibrium experiences a zero net force
The geocentric model, in all of its complexity, survived scientific scrutiny for almost 1,400 years. However, in modern astronomy, scientists seek to explain the natural and physical world we live in as simply as possible. The complexity of Ptolemy's model was an indicator that his theory was inherently flawed. Why, then, was the geocentric model the leading theory for such a long time, even though the heliocentric model more simply explained the observed motions and brightness of the planets? Choose all that apply: Ancient astronomers did not observe stellar parallax, which would have provided evidence in favor of the heliocentric model, The complexity of the geocentric model was appealing to most ancient astronomers, The heliocentric model did not make noticeably better predictions than the geocentric model, From Earth, all heavenly bodies appeared to circle around a stationary Earth, The geocentric model conformed to both the philosophical and religious doctrines of the time,
Ancient astronomers did not observe stellar parallax, which would have provided evidence in favor of the heliocentric model, The heliocentric model did not make noticeably better predictions than the geocentric model, From Earth, all heavenly bodies appeared to circle around a stationary Earth, The geocentric model conformed to both the philosophical and religious doctrines of the time,
In the figure below, label the essential components used to triangulate the distance to the tree located on the opposite side of the river (assume the baseline remains constant). Choices: Baseline, Distance to Object, Right Angle, Angle that Increases with Increasing Distance to Object, Angle that Decreases with Increasing Distance to Object, Label A
Angle that Decreases with Increasing Distance to Object
In the figure below, label the essential components used to triangulate the distance to the tree located on the opposite side of the river (assume the baseline remains constant). Choices: Baseline, Distance to Object, Right Angle, Angle that Increases with Increasing Distance to Object, Angle that Decreases with Increasing Distance to Object, Label E
Angle that Increases with Increasing Distance to Object
When Dr. Hewitt drops a book and a crumpled piece of paper together from the same height, which object hits the ground first, and why? The heavier object--the book--hits the ground first because it experiences a greater force of gravitational attraction from Earth The lighter object--the crumpled paper--hits the ground first because it is easier for gravity to influence its motion since it is light Both objects hit the ground at the same time because air resistance is negligible
Both objects hit the ground at the same time because air resistance is negligible
The weights of Burl, Paul, and the scaffold produce tensions in the supporting ropes. Rank the tension in the left rope, from most to least, in the three situations, A, B, and C.
C, B, A
Three pucks, A, B, and C, are shown sliding across ice at the noted speeds. Air and ice friction forces are negligible. Rank them, from greatest to least, by the force needed to stop them in the same time interval.
C, B, A
A track is made of a piece of channel iron bent as shown. A ball released at the left end of the track continues past the various points. Rank the speed of the ball at points A, B, C, and D, from fastest to slowest. Watch for tie scores.
C, B=D, A
In the figure below, label the essential components used to triangulate the distance to the tree located on the opposite side of the river (assume the baseline remains constant). Choices: Baseline, Distance to Object, Right Angle, Angle that Increases with Increasing Distance to Object, Angle that Decreases with Increasing Distance to Object, Label B
Distance to Object
Pseudoscience is best characterized as being: An alternate view to be taken seriously, New age, Fake, All of the above,
Fake
What relationship between distance traveled and time did Galileo discover for freely falling objects released from rest? Galileo discovered that distance was independent of time Galileo discovered that distance increased as the time squared Galileo discovered that distance increased inversely proportional to time Galileo discovered that distance increased proportional to time.
Galileo discovered that distance increased as the time squared
What did Galileo discover in his legendary experiment on the Leaning Tower of Pisa? Galileo found that air resistance significantly slowed falling stones, Galileo found that stones fall faster proportional to their weight, Galileo found that a heavier stone does not fall significantly faster than a lighter one, Galileo found that a heavier stone falls significantly faster than a lighter one,
Galileo found that a heavier stone does not fall significantly faster than a lighter one
Copernicus's heliocentric model and Ptolemy's geocentric model were each developed to provide a description of the solar system. Both models had advantages that made each an acceptable explanation for motions in the solar system during their time. Sort each statement according to whether it is an advantage of the heliocentric model, the geocentric model, or both: Planetary orbits and motions based on Greek ideologies of perfect form and motion, Rooted in widely accepted religious beliefs regarding Earth's place in the universe, Explained planetary motions and brightness changes most simply, Predicted planetary positions accurately over relatively short time periods,
Geocentric: Rooted in widely accepted religious beliefs regarding Earth's place in the universe, Heliocentric: Explained planetary motions and brightness changes most simply, Both: Predicted planetary positions accurately over relatively short time periods, Planetary orbits and motions based on Greek ideologies of perfect form and motion,
Two competing models attempt to explain the motions and changing brightness of the planets: Ptolemy's geocentric model and Copernicus' heliocentric model. Sort the characteristics according to whether they are part of the geocentric model, the heliocentric model, or both solar system models: This model is Earth-centered, Retrograde motion is explained by epicycles, The brightness of a planet increases when the planet is closest to Earth, This model is Sun-centered, Retrograde motion is explained by the orbital speeds of planets, Epicycles and deferents help explain planetary motion, Planets move in circular orbits and with uniform motion,
Geocentric: This model is Earth-centered, Retrograde motion is explained by epicycles, Heliocentric: This model is Sun-centered, Retrograde motion is explained by the orbital speeds of planets, Both: Epicycles and deferents help explain planetary motion, Planets move in circular orbits and with uniform motion, The brightness of a planet increases when the planet is closest to Earth,
What kind of speed is registered by an automobile speedometer? Maximum speed, Instantaneous speed, Minimum speed, Average speed,
Instantaneous speed
What type of path does a moving object follow in the absence of a force? It continues to move in a straight line at a constant speed, It moves in a straight line and eventually slows to a stop, It follows a parabolic trajectory in the absence of a force, It follows a circular path in the absence of a force,
It continues to move in a straight line at a constant speed
What is the distance fallen for a freely falling object 1 s after being dropped from a rest position? What is the distance for a 4-s drop? It falls 5 m in 1 s and 80 m in 4 s It falls 10 m in 1 s and 160 m in 4 s It falls 5 m in 1 s and 20 m in 4 s It falls 5 m in 1 s and 5 m in 4 s
It falls 5 m in 1 s and 80 m in 4 s
If a car is moving at 90 km/h and it rounds a corner, also at 90 km/h, does it maintain a constant speed? A constant velocity? It maintains a constant velocity, but not a constant speed, It maintains a constant speed and a constant velocity, It maintains a constant speed, but does not maintain a constant velocity, It does not maintain a constant speed or a constant velocity,
It maintains a constant speed, but does not maintain a constant velocity
Why are students of the arts encouraged to learn about science and science students encouraged to learn about the arts? Knowing both the arts and sciences makes for a wholeness in the way we view the world, Scientists need to relax by viewing art and artists need the discipline of learning science, Scientists need to learn to draw and artists need to learn how to solve equations, Scientists need to learn how to write and writers need to learn what is impossible to do according to science,
Knowing both the arts and sciences makes for a wholeness in the way we view the world
The rope supports a lantern that weighs 50 N. Is the tension in the rope less than, equal to, or greater than 50 N?
Less
If the pinhole is made large, what is the main effect on the illuminated region? You do not see a large change in the illuminated region but makes the measurement of the distances more difficult, You mainly observe a changed shape, You see a large change in the illuminated area, You see a large change in the size of the illuminated area and a change in its shape, You see a large change in the illuminated and a its edges become blurry, Mainly, the edge of the illuminated region is not as sharp,
Mainly, the edge of the illuminated region is not as sharp
What determines the shape of the illuminated region? A combination of the shape of the object (the Sun or the lamp), the shape of the pinhole and the direction of propagation of the light, A combination of the shape of the object (the Sun or the lamp) and the shape of the pinhole, The shape of the pinhole and the direction of propagation of the light, A combination of the shape of the object (the Sun or the lamp) and the direction of propagation of the light, Mostly, it is determined by the shape of the object (the Sun or the lamp), Mostly, it is determined by the shape of the pinhole,
Mostly, it is determined by the shape of the object (the Sun or the lamp)
When you hang one reference object from a rubber band you obtain one unit of deformation. Consider the case where you hang this system from another rubber band, so that you have two rubber bands, vertical, one after another. What is the deformation of the bands? Ignore the weight of the bands. You are still only using one reference object. One unit of deformation in both of the bands, Half unit of deformation in each of the bands, Two units of deformation in each of the bands, Two units of deformation in the top band and one unit of deformation in the bottom band, One unit of deformation in the top band and two units of deformation in the bottom band, Half unit of deformation in the top band and one unit of deformation in the bottom band,
One unit of deformation in both of the bands
You pull one rubber band with one finger from each hand until it shows 2 units of deformation. Which of the following combinations of rubber bands produce the same force experience on your fingers? Pulling two rubber bands at the same time so that they also reach 2 units of deformation, Pulling two rubber bands at the same time so that they reach 1 unit of deformation, Attaching two rubber bands, one after another, and pulling from the free ends so that each has 1 unit of deformation, Attaching two rubber bands, one after another, and pulling from the free ends so that each has 2 units of deformation, Pulling two rubber bands at the same time so that they reach 1/2 unit of deformation, Pulling two rubber bands at the same time so that they reach 4 units of deformation,
Pulling two rubber bands at the same time so that they reach 1 unit of deformation
One way to triangulate the distance to many remote objects, such as stars, is to observe the shifts in their location relative to more distant background objects. This apparent shifting of an object's location with respect to the background objects is known as parallax. Parallax is represented in the figure, where the top image shows the parallax shift that is observed along a baseline that runs from one side of Earth to the other. The bottom two images show what the observer sees from opposite sides of Earth. Using triangulation, the distance to the object can be calculated with simple trigonometric relations. Use the figure to determine how the measured parallax changes the following situation: As the distance to background objects increases, parallax: Increases, Decreases, Remains the Same,
Remains the Same
In the figure below, label the essential components used to triangulate the distance to the tree located on the opposite side of the river (assume the baseline remains constant). Choices: Baseline, Distance to Object, Right Angle, Angle that Increases with Increasing Distance to Object, Angle that Decreases with Increasing Distance to Object, Label C
Right Angle
Clearly distinguish between science and technology. Science is applied technology, Technology solves problems, whereas science creates them, Science gathers the knowledge that technology uses for practical purposes, Technology can be helpful or harmful, while science is only helpful.
Science gathers the knowledge that technology uses for practical purposes
A force of gravity pulls downward on a book on a table. What force prevents the book from accelerating downward? Gravitational force. Force of friction, Support (Normal) force, Net force,
Support (Normal) force
A different scaffold that weighs 400 N supports two painters, one 500 N and the other 400 N. The reading in the left scale is 800 N. What is the reading in the right-hand scale (T)?
T = 500 N
Listed following are a series of statements that each make a claim. Classify these as either testable by accepted methods of science or non-testable by accepted methods of science. Be sure to note that this question does not ask whether a statement would pass or fail a test; it only asks whether it is testable in principle. Bacteria acquire resistance to antibiotics through changes in their DNA, Vince Young is the greatest quarterback of all time, Mars once had liquid water on its surface, There will be a solar eclipse next Tuesday at 11 a.m, Earth orbits the Sun every 365.25 days, Hurricane Katrina was an act of God, People born under the sign of Sagittarius are twice as likely to be teachers as anyone else,
Testable: Bacteria acquire resistance to antibiotics through changes in their DNA. Mars once had liquid water on its surface. There will be a solar eclipse next Tuesday at 11 a.m. Earth orbits the Sun every 365.25 days. People born under the sign of Sagittarius are twice as likely to be teachers as anyone else.
How does the Moon's diameter compare with the distance between Earth and the Moon? The Moon's diameter is equal to the distance between Earth and the Moon, The Moon's diameter is 1/2.5 times the distance between Earth and the Moon, The Moon's diameter is 1/110 the distance between Earth and the Moon, The Moon's diameter is 1/3.5 times the distance between Earth and the Moon,
The Moon's diameter is 1/110 the distance between Earth and the Moon
If the distance from the light source to the pinhole is doubled, what happens to the area of the illuminated region? The area is half as large, The area is one quarter as large, The area remains the same, The area is 3.14 times as large, The area doubles in size, The area is now four times as large,
The area is one quarter as large
Based on the experiment that Dr. Hewitt demonstrated in the video, what factors determine whether the air resistance experienced by a falling object will affect the motion of the object? The area of the object in relation to the weight of the object determines the air resistance the object experiences. Objects having greater area but smaller weight experience greater effect of air resistance The weight of the object alone determines whether the air resistance it experiences will have a greater effect on the motion. Heavier objects experience greater effects due to air resistance on their motion The area of the object alone determines whether the air resistance it experiences will have a greater effect on the motion. Objects having smaller area experience greater air resistance
The area of the object in relation to the weight of the object determines the air resistance the object experiences. Objects having greater area but smaller weight experience greater effect of air resistance
Dr. Hewitt has clay "blobs" hanging on either side of his head in this video. When he turns around, what happens to the blobs? The blobs fall off Dr. Hewitt's head, The blobs turn around in the same direction as Dr. Hewitt, The blobs tend to stay where they were, The blobs turn around in the opposite direction from Dr. Hewitt,
The blobs tend to stay where they were
According to the parallelogram rule, what quantity is represented by the diagonal of a constructed parallelogram? The diagonal is always 1.41 times the magnitude of the sum of the vectors, The diagonal is the resultant, or sum, of two vectors, The diagonal is the difference of two vectors, The diagonal is 1.41 times the magnitude of the longest vector,
The diagonal is the resultant, or sum, of two vectors
For the determination of the size of the sun, the experiment requires a piece of information that is not directly measured. This is: The speed of light, Width of the Sun image, The size of the Earth, Elevation of the pinhole, The distance from Earth to Sun, The radius of the Sun,
The distance from Earth to Sun
If you push on a crate with a horizontal force of 100 N and it slides at constant velocity, what is the magnitude and direction of the frictional force acting on the crate? The frictional force has nothing to do with you pushing on the crate, The frictional force on the crate is zero newtons, The frictional force on the crate is 100 N opposite the direction of motion, The frictional force on the crate is 100 N in the same direction as the direction of motion,
The frictional force on the crate is 100 N opposite the direction of motion
Which is more likely to break: a hammock stretched tightly between a pair of trees or one that sags more when you sit on it? Both hammocks are equally likely to break, The hammock that sags more when you sit on it is more likely to break, The hammock stretched tightly between a pair of trees is more likely to break,
The hammock stretched tightly between a pair of trees is more likely to break
In the video, Dr. Hewitt drops a book and a flat piece of paper together from the same height, and one object hits the ground before the other. Why does that object hit the ground first? The lighter object--the paper--hits the ground first because it easier for gravity to influence its motion The lighter object--the paper--hits the ground first because lighter objects have lower inertia and move more easily than heavier objects The heavier object hits the ground first because it experiences a greater force of gravitational attraction from Earth The heavier object--the book--hits the ground first because the other, lighter, object is more influenced by air resistance Both objects strike at the same time because the heavier object experiences greater gravitational force, but it also has greater inertia The lighter object has less gravitational force, but it also has smaller inertia
The heavier object--the book--hits the ground first because the other, lighter, object is more influenced by air resistance
Which quantity cannot be determined from the experiment? The volume of the Sun, The radius of the Sun, The area of the Sun, The mass of the Sun, The perimeter of a cross section of the Sun that passes by its center, The diameter of the Sun,
The mass of the Sun
In the experiment you used objects with masses that were not necessarily known. Assume that for a certain object you observed a deformation of size 3. Next, you remove that object and hang a second, different object, made of different materials, and observe that the deformation is the same. What can you say about the mass of the second object compared to the first? Select, the correct answer and the best argument for it. There is no relation between the masses since they are not made of the same materials, There is no relation between the masses, but they must have the same density to be able to extend the bands equally, The masses are equal. Objects of equal mass have the same weight, which is the force producing the deformation, The masses are equal. When the deformations are the same, this indicates the densities of the materials are the same, There is no relation between the masses, Their weight is the same as shown by the equal deformation, but weight is not directly related to mass, The masses are equal. The deformation is the same and this indicates that the inertia of the objects is also equal,
The masses are equal. Objects of equal mass have the same weight, which is the force producing the deformation
When Dr. Hewitt pulls the tablecloth, why do the items on the tablecloth do what they do? Friction with the tablecloth is keeping them there, Their inertia is sufficient to keep them there, They are attached to the tablecloth, Friction with the table is keeping them there,
Their inertia is sufficient to keep them there
What are the circular spots of light seen on the ground beneath a tree on a sunny day? These are blurry images of the point of light that is the Sun, These are images of holes in leaves, These are pinhole images of the Sun, These are images of holes formed by gaps between leaves,
These are pinhole images of the Sun
Why do the clay blobs do what they do when Dr. Hewitt turns around? Dr. Hewitt is holding them there, Dr. Hewitt is turning them back to their original position, They have inertia−−the tendency of an object at rest to stay at rest, Friction with the head is keeping them there,
They have inertia--the tendency of an object at rest to stay at rest
Why do the alphabet letters tend to do what they do when you rotate the bowl? The sides of the soup bowl prevent the letters from moving, The soup prevents the letters from moving, The letters are heavier than the soup, so they cannot move even though the soup moves, They have inertia−−the tendency of an object at rest to stay at rest,
They have inertia−−the tendency of an object at rest to stay at rest
When Dr. Hewitt pulls the tablecloth, what happens to the items on the tablecloth? They tend to stay where they were, They move horizontally in the opposite direction from the tablecloth, They move horizontally in the same direction as the tablecloth, They move vertically upward,
They tend to stay where they were
Similar to the case in the experiment you use two rubber bands, side to side first, to hold a weight of 3 reference objects. Then, as in the experiment, the bands are pulled apart in their free ends until they form an angle of 30 degrees with respect to the horizontal. What are the deformations observed in these bands? One unit of deformation, One and one half units of deformation, Two units of deformation, Two and one half units of deformation, Three units of deformation, Four units of deformation,
Three units of deformation
Which of the following are scientific hypotheses? Check all that apply. Tides are caused by the Moon, Earth rotates about its axis because living things need an alternation of light and darkness, Chlorophyll makes grass green.
Tides are caused by the Moon, Chlorophyll makes grass green
When you stretch a rubber band with a pair of fingers, what is the number of forces that should be used to described the action of your hand on the rubber band? Select the number and the associated explanation. Ignore the weight of the band. One force. The band is interacting with just one object, your hand, One force. The band is subject only to the net force on it, Two forces. One pulling at each end of the band, Two forces. One pulling and one pushing, to obtain equilibrium, Two or more forces. At least two are necessary but more are possible, depending on the relative orientation of the band, Two or more forces. The number is not only determined by the interaction with the hand but must also include other details of the system,
Two forces. One pulling at each end of the band
Some alphabet letters are floating in a bowl of soup. You want to move a letter that is far away from you closer to you. How could you rotate the bowl to do that? Rotate the bowl either clockwise or counterclockwise, depending on where the letter is located, Unfortunately, neither rotating the bowl clockwise nor rotating it counterclockwise will work, Rotate the bowl clockwise, Rotate the bowl counterclockwise,
Unfortunately, neither rotating the bowl clockwise nor rotating it counterclockwise will work
The sketch shows a painter's scaffold in mechanical equilibrium. The person in the middle weighs 500 N, and the tensions in each rope are 400 N. What is the weight of the scaffold (W)?
W = 300 N
In daily life, people are often praised for maintaining some particular point of view, for the "courage of their convictions." A change of mind is seen as a sign of weakness. How is this different in science? When a scientist finds evidence that contradicts a law, then the law must be abandoned, Scientific laws are decided to be true by majority vote, Once a scientific law is discovered, it never changes, so you must change your mind to believe it, When a famous scientist restates a law, then the old law must be abandoned,
When a scientist finds evidence that contradicts a law, then the law must be abandoned
Acceleration is generally defined as the time rate of change of velocity. When can it be defined as the time rate of change of speed? When moving in a circle, the time rate of change of speed is always zero When moving in a circle, the time rate of change of speed is called average speed When moving in a straight line, the time rate of change of speed is acceleration When moving in a straight line, the time rate of change of speed is called velocity
When moving in a straight line, the time rate of change of speed is acceleration
Stand next to a wall that travels at 30 km/s relative to the Sun. With your feet on the ground, you also travel at the same 30 km/s. Do you maintain this speed when your feet leave the ground? What concept supports your answer? When you jump, you continue to move at 30 km/s due to your inertia, When you jump, your velocity relative to the Sun drops to zero due to inertia, When you jump, your velocity relative to the Sun goes to zero because the forces on you are in equilibrium, When you jump, your velocity relative to the Sun changes to -30 km/s so that your velocity relative to the wall is zero, because the forces on you are in equilibrium,
When you jump, you continue to move at 30 km/s due to your inertia
As you read this in your chair, how fast are you moving relative to the chair? Relative to the Sun? You are moving over 100,000 km/h relative to the chair and the Sun, You are not moving relative to the chair, and you are not moving relative to the Sun, You are stationary relative to the Sun, but you are moving relative to the chair, You are not moving relative to the chair, but you are moving over 100,000 km/h relative to the Sun,
You are not moving relative to the chair, but you are moving over 100,000 km/h relative to the Sun
You tell your friend about the neat tablecloth trick that Dr. Hewitt demonstrated. Your friend tries to repeat this trick at home and later complains to you that it failed. Which of the following is most likely the reason that it failed? Your friend is too clumsy, Your friend pulled the tablecloth too slowly, The items placed on the tablecloth were too light, Your friend pulled the tablecloth too quickly,
Your friend pulled the tablecloth too slowly
When you stand at rest on a bathroom scale, how does your weight compare with the support force from the scale? Your weight is equal in magnitude and in the same direction as the support force from the scale, Your weight is equal in magnitude and opposite in direction to the support force from the scale, The support force from the scale is half your weight, The support force from the scale is twice your weight,
Your weight is equal in magnitude and opposite in direction to the support force from the scale
Select the correct equations that show that a freely falling rock drops a distance of 45 m when it falls from rest for 3 s . A free falling object starting at rest is equal to: (g*t^2)/2
d = (10 m/s^2*3 s^2)/2
Surprisingly, very few athletes can jump more than 2 feet (0.6 mm) straight up. Use d=1/2*gt^2and solve for the time one spends moving upward in a 0.6-mm vertical jump. Then double it for the "hang time"-the time one's feet are off the ground.
t = 0.70 s
A ball is tossed with enough speed straight up so that it is in the air several seconds. Assume upward direction is positive and downward is negative. What is the velocity of the ball when it reaches its highest point?
v = 0 m/s
Select the correct equations that show that the average speed of a rabbit that runs a distance of 39 m in a time of 3 s is 13 m/s. [Average speed is equal to (total distance)/(time interval)]
v = [39 m] / [3 s]
State the equilibrium rule for forces in symbolic notation ΣF = 0 ΣF = 2 mg ΣF = -mg ΣF = net force
ΣF = 0
