physics exam objectives
Solve problems using the law of conservation of momentum.
(net mv)before= (net mv) after (mx10)before= (2m x V) after V= 5m/s
Understand that when an object is accelerating, its velocity is changing. This can either be a change in speed, direction or both
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Be able to express the unit of Newton in terms of base units.
1 g= .1 kg= 1 N F= ma N=kg x m/s^2
Discuss how an unbalanced force acting on an object over an interval of time produces a change in its momentum (F*t = Dmv). This includes the three cases of how impulse changes momentum discussed in the slides.
A force acting for a given amount of time will change an object's momentum. Put another way, an unbalanced force always accelerates an object - either speeding it up or slowing it down. If the force acts opposite the object's motion, it slows the object down. Case 1: increasing momentum (apply the greatest force for as long as possible and you extend the time of contact) i.e following through with swing Case 2: decreasing momentum over a long time (extend the time during which momentum is reduced) i.e bending knees when jump Case 3: decreasing momentum over a short time (short time produces large force) i.e karate chop
Define acceleration and demonstrate the ability to calculate it.
Acceleration is a vector quantity that is defined as the rate at which an object changes its velocity. An object is accelerating if it is changing its velocity.
Show how objects in a dark room will appear in different colors if illuminated with different colors of light (using a flashlight and various color filters). Include a discussion about the "colors" in various lights and in the sun.
An object can reflect only those frequencies that are present in illuminating light The appearance of colored object depends on the kind of light that illuminates it Incandescent lamp- emits more light in lower than higher frequencies Enhancing any reds viewed in this light Fluorescent lamp- richer in higher frequencies Blues are enhanced under this light Objects "true" color is defined as the color it has in daylight When shopping for clothes you should go out into the sun to see the "true" color if that is the lighting you will be wearing the outfit in
Explain a mirage.
An optical illusion caused by atmospheric conditions, which causes the appearance of a sheet of water in a desert or on a hot road caused by refraction of light from the sky by heated air . A mirage. The apparent wetness of the road is not a reflection of the sky by water, but, rather, refraction of sky light through the hotter and less dense air near the road surface
Distinguish between average speed and average velocity.
Average speed- of an object is the total distance traveled by the object divided by the elapsed time to cover that distance Average velocity- ^
Define average velocity and demonstrate the ability to calculate it.
Average velocity- distance traveled divided by the time elapsed
Describe spherical and chromatic aberration in lenses and explain how these defects can be reduced.
Chromatic aberration in lenses, in essence spreading out of colors Take advantage of refraction have spreading of colors
Explain the classification of the spectrum according to frequency
Classification of electromagnetic waves according to frequency: radio, micro, infrared, visible, ultraviolet, x-rays, and gammas Highest we can see appears violet Higher is ultraviolet- more energetic causes sunburns Lowest we can see appears red
Why clouds are white. (514)
Clouds- clusters of various size of water droplets Size of clusters determines scattered cloud color Tiny colors produce bluish clouds Slightly large clusters produce greenish clouds Larger clusters produce reddish clouds Overall result is white clouds Slightly larger clusters produce a deep gray Still larger clusters produce rain drops small: when light comes in and hit particles (excites) its the dispersion of all light in different directions. Each droplet absorbs the light. big: reflect and refract, which causes some light to get absorbed and the more it happens the less light that comes out the other side.
Explain the arguments that were used to refute Copernicus' Moving Earth idea and why these arguments were incorrect
Corpoernicus' proposed that Earth was moving, circulating the Sun. The concept of inertia was not yet understood. The idea was refuted and people argued that the force required to keep Earth moving was beyond imagination. If Copernicus were correct, Earth would have to travel at a speed of 107,000 kilometers per hour to circle the Sun in one year. Example of argument: think about a bird sitting at rest at the top of a tall tree, on the ground below is a worm, the bird sees the worm and drops vertically to catch it. People exclaimed that this example would be impossible if Earth moved, as Copernicus suggested. Even if the bird could descend from its branch in 1 second people would argue that the worm would have been swept by the moving Earth a distance of 30 Kilometers away. It would be impossible for a bird to drop straight down and catch a worm. But birds in fact DO catch worms from high tree branches, which seemed to be clear evidence that Earth must be at rest. Refute: you can refute this argument by explaining the idea of inertia- the property of things to resist changes in motion. Not only is Earth moving at 30 Kilometers per second but so are the trees, the branch of the tree, the bird on the branch, the worm blow, and even the air in between. All are moving at 30 Kilometers per second. Things in motion remain in motion if no unbalanced forces are acting upon them. So when the bird drops from the branch, its initial sideways motion of 30 kilometers per second remains unchanged. It catches the worm, quite unaffected by the motion of its total environment.
Define refraction and predict whether a ray will be bent toward or away from the normal when light moves from one medium to another.
Definition is on quizlet Light ray passes a boundary Travels fast -> slow (bend towards normal line) Travels slow -> fast (bend aways from normal line)
Explain why diamonds sparkle.
Diamonds are cut so that a light ray falling on the diamond is reflected multiple times inside the diamond and therefore sends light out in all directions Cut is important because determines the shape (reflection...)
Distinguish between specular (clear) and diffuse reflection and give examples.
Diffuse is when light strikes a rough or irregular surface and reflects in different directions example : ghost image that occurs on TV set when TV signals bounce off builds and on rough roads (allows to see the road ahead of the car at night) Specular is when the incident light is reflected into a single outgoing direction example: reflections on still water
Explain Galileo's concept of inertia, including the experiments he did to study it.
Discovery: Objects of different weight fall on the ground at the same time in the absence of air resistance A moving object needs no force to keep it moving in the absence of friction Inertia: the property of matter to resist changes in motion, depends on the amount of matter in an object (mass) DUE TO FRICTION NOT "NATURE"
Explain dispersion of light and its role in the formation of rainbows.
Dispersion happens Result light slows down for different colors Net result rainbows, prism effect Know diagrams where light comes into droplet (maybe have different colored pencils) As the light reflects back out of the raindrop, it bends again. That internal reflection produces the arc of sunlight spread out across its spectrum of colors -- a rainbow. Pigott said a double rainbow is formed when there are two reflections inside a raindrop.
Name and explain the early examples of scientific measurements discussed in class.
Distance and the Size of the Moon Diameter of the Earth
.Define efficiency and be able to solve problems involving it.
Efficiency: The percentage of the work put into a machine that is converted into useful work output (more generally, useful energy output divided by the total energy input)
Explain the difference between elastic and inelastic collisions, understanding the special circumstances of bouncing.
Elastic: occurs when colliding objects rebound without lasting deformation or any generation of heat Inelastic: occurs when colliding object result in deformation and/ or the generation of heat Bouncing: impulses are generally greater when objects bounce, i.e pelton wheel designed to "bounce" water. Combined effect of force and time.
Recognize that visible light is an electromagnetic wave with a specific wavelength range
Electromagnetic Waves: originates from the accelerated motion of electrons Summarize, wavelengths have different ranges, or lengths of frequencies (radio-gamma rays)
Explain in detail Newton's First Law of Motion.
Every object continues in a state of rest or of uniform speed in a straight line unless acted on by a nonzero net force
Demonstrate an understanding that when one object exerts a force on a second object, the second object always exerts a force of equal magnitude and in the opposite direction. This force-pair always happens simultaneously (Newton's third law).
Ex. When a person pushes with their fingers on a wall, the wall pushes back. This is shown when the person's fingers bend. Pair of forces involved These forces equal in magnitude(have the same strength) opposite in direction
Explain the effect of mass has on acceleration, giving examples where forces with equal magnitudes and opposite directions can cause one object to have a large acceleration and the other object a small acceleration.
F/m= a F/M=a When analyzing changes in motion, Newton's second law tells is that we must consider masses involved. Cannonball example when you compare the movement of ball to canon Formulas show who change in velocity of cannonball is so large compared to change in velocity of canon Earth reacting to falling object for example Earth's acceleration towards the falling object would be microscopic. Can clearly see an object falling though because it's acceleration is much bigger (add more)
7.Explain why, in reality, a heavy object in free fall will indeed accelerate downward close to 'g' and that the light object will accelerate at a rate less than 'g'.
F/m= g Heavy objects will accelerate downward close to g because the object's mass and net force applied when dropping the object is greater than the force of air resistance acting upon it The lighter object will be more affected by the air resistance Ex. when drop a book and paper the book falls first and the paper goes side ways in the air because the air resistance affects the paper a lot More? Clearer explanation?
Define force and distinguish between contact forces and non-contact (field) force
Force: vectors (magnitude and direction) push or pull, but no push or pull ever occurs alone every force is part of an interaction between one thing and another Ex. when push a wall the wall pushes back on you, your finger bend These forces are equal in magnitude and opposite in direction and constitute single interaction Exerter or receiver Must be treated equally Forces depend on friction Forces occur in forcepairs Neither force exists without other Contact forces: forces that have an effect only on objects that they touch Net forces: the vector sum of forces that act on an object Non-contact: forces that do not physically touch an object Ex: gravity
Describe the motion of an object in free-fall from rest and understand that free-fall means falling only under the action of the force of gravity and no other forces.
Free Fall is the term that describes the acceleration of objects toward the Earth when dropped at rest. The acceleration of the falling object is due to the force of gravity between the object and the earth.
Define free fall, explaining why (in a vacuum) a heavier object accelerates the same as a lighter object.
Free Fall: an object under the influence of gravity only In a vacuum there is no air resistance to the objects accelerate at the same time with the force acting on it The gravitational force on both objects are the same 10m/s^2 therefore they accelerate at the same speed When objects are not in a vacuum the heavier object accelerates faster and reaches terminal velocity slower, meaning it hits the ground force because the air resistance compared to the weight of the object is small
Interpret free-body diagrams and understand the meaning of net force and equilibrium
Free body diagram: a valuable tool used to study forces; uses vectors to show all of the forces acting on an object; does not include the forces an object exerts on other things; draw only the objects you are studying, not any other objects around Equilibrium: the state of an object or system of objects for which there are no changes in motion. In accord with Newton's first law, if an object is at rest, the state of rest persists. If an object is moving, its motion continues without change. Equilibrium Rule: For any object or system of objects in equilibrium, the sum of forces acting equals zero. In equation form F=0 Static Dynamic Net force: the vector sum of forces that act on an object
Determine the speed and distance fallen at any time for a free-falling object that is dropped from rest.
Free fall- object that falls at influence of gravity only During each second of fall, the object gains a speed of 10 meters per second This gain per second is known as the acceleration Free-fall acceleration known as approximately equal to 10 meters per second each second 10 m/s^2 Free falling normal to use g to represent acceleration (because acceleration is due to gravity) The instantaneous speed or velocity of an object falling from rest is consistent with thee equation Galileo "made" Velocity acquired= acceleration X time
Define the friction force and explain its cause.
Friction: when surfaces slide or tend to slide over one another, a force of friction acts Results from irregularities and mutual attractions between atoms in surfaces of sliding objects Friction does not occur when an object is at rest, there must be a nonzero net force acting (causing acceleration) Static and Sliding
Explain what Galileo discovered about the amount of speed a ball gained each second when rolling down an incline plane, including the relationship for velocity he discovered.
Galileo discovered that a ball rolling down an inclined plane picks up the same amount of speed in successive seconds, that is the ball rolls with unchanging acceleration - constant acceleration. The gain per second is its acceleration. As the steepness of the incline increases, the acceleration also increases. Galileo found that the distance a uniformly accelerating object travels is proportional to the square of time. The distance traveled by a uniformly accelerating object starting from rest is: Distance traveled = ½ (acceleration x time x time) Discover the property called inertia
State the law of conservation of momentum and recognize the conditions under which momentum is conserved.
In the absence of an external force, the momentum of a system remains unchanged When no external force is present, no external impulse is present, and no change in momentum is possible
Explain that energy is a conserved quantity and is made up of kinetic and potential energies.
Kinetic Energy: Energy that something possesses because of its motion, quantified by the relationship Kinetic energy= 1/2 mv ^2 Potential Energy: Energy that something possesses because of its position Potential energy has significance only when it changes- does work or transforms energy into some other form. Conservation of Energy: The work output of any machine cannot exceed the work input. In an ideal machine, where no energy is transformed into thermal energy Law of conservation of energy: Energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes.
Define mechanical, kinetic and potential energy and be able to calculate KE = (1/2)mv2.
Kinetic Energy:Energy that something possesses because of its motion, quantified by the relationship Kinetic energy= 1/2 mv ^2 Potential Energy: Energy that something possesses because of its position
Solve problems involving the speed of light.
Light shining on metal forces free electrons in the metal into vibration that emit their own light as reflection Light incident on Dry surfaces bounce directly in eye Wet surfaces bounce inside the transparent wet region, absorbing energy with each bounce, and reaches eye darker Lateral inhibition We don't perceive the actual differences in brightness
Why sunsets are red; (512)
Light that is least scattered is light of low frequencies, which best travel through air Light that is not scattered light that is transmitted Red, Orange, yellow light are least scattered by the atmosphere, light of these lower frequencies is better transmitted through air Red, scattered least, therefore is transmitted the most, passes through more atmosphere than any other color So thicker atmosphere through which a beam of sunlight travels, the more the higher- frequency components of the light are scattered out of the beam Light makes it through the best at red Sunlight travels through more atmosphere at sunset, why the sun is red
.Demonstrate the understanding that simple machines do not increase the amount of work. Describe why simple machines are useful and recognize the six basic simple machines.
Machine: A device, such as a lever or pulley, that increases (or decreases) a force or simply changes the direction of a force. Principle of a machine Conservation of energy concept: Work input= work output Input force x input distance = output distance Force x distance (input) = force x distance (output) Simplest Machine Pulley Operates like a lever with equal arms changes the direction of the input force Operates as a system of pulleys (block and tackle) Work- Energy theorem: the work done on an object equals the change in the kinetic energy of the object: (work can also transfer other forms of energy to a system) Ex. when a car speeds up, its gain in kinetic energy comes from work done on it. Or, when a moving car slows, work is done to reduce its kinetic energy. Six basic machines: Lever: a simple machine consisting of a rigid rod pivoted at a fixed point called the fulcrum Wheel and axle Pulley Inclined plane Wedge Screw
Explain why a feather and a coin fall with unequal accelerations and why, in a vacuum, they fall at the same rate.
Many objects fall with unequal accelerations This is because of air resistance Feather and coin fall with quite different accelerations. But, if the air in the tube is removed by a vacuum pump and the tub is quickly inverted, the feather and coin fall with the same acceleration Although air resistance appreciably alters motion of things luke falling feathers, the motion of heavier objects like stones and baseballs at ordinary low speeds is not appreciably affected by air The relationships v=gt and d=1/2gt^2 These can be used to obtain very good approximation for most objects falling in air from an initial position of rest
Be able to explain the relationship between mass and inertia, mass and weight as well as mass and volume.
Mass: the quantity of matter in an object Measure of the inertia or sluggishness that an object exhibits in response to any effort made to start it, stop it, or change its state of motion Weight: usually the force upon an object due to gravity W=mg Mass stays the same no matter where you are, weight changes when the force of gravity changes G on earth is 10 m/s^2 Volume: the quantity of space an object occupies NOT good indication of an object's mass
Demonstrate an understanding of the formation of color by mixing pigment colors or dyes.
Mixing pigments in paints and dye is completely different than mixing lights When combining pigments, if combine all colors the color you see becomes muddy brown Compared to light that is white when all colors mix Pigments: tiny particles that absorb specific colors An example of using pigment is colored printing Inkjet printers have magenta, yellow, and cyan and sometimes black cartridges which then mix in different layers to form a "colored picture" Also the overlapping of the subtractive primary colors produce different colors necessary to make out pictures
Explain that momentum is a conserved quantity.
Momentum is a conserved quantity; the momentum of an object is never changed. The momentum of an object varies directly with the speed of the object. Two objects of different mass are moving at the same speed; the more massive object will have the greatest momentum.
Define the momentum (p) and calculate it using p = m*v.
Momentum: The product of the mass of an object and its velocity
Explain how objects reflect light to determine the color we see them to be. (506)
Most objects around us reflect light rather than emit light Except for these light sources Lamps Lasers Gas discharge tubes Only reflect part of the light that is incident upon them Objects reflect specific colors of light because Different materials have different natural frequencies for absorbing and emitting electromagnetic radiation At the resonant frequencies at which the amplitudes of oscillation are large, light is absorbed, butat frequencies below and above resonant frequencies, light is reemitted Usually material absorbs light of some frequencies and reflects the rest All of the colors that are absorbed we cannot see, but the colors that are reflected we see Ex. a red rose absorbs all light other than red
Explain how the eye focuses light to form images; be able to name the major components of the eye.
Muscles in the colored part of your eye, called the iris, control your pupil size. Your pupils get bigger or smaller, depending on the amount of light around you. ... When it's bright, they get smaller, or constrict, to let in less light. Sometimes your pupils can dilate without any change in the light
Explain Aristotle's ideas of motion, including to what extent these ideas have been shown to be inaccurate
Natural Motion: Every object in the universe has a proper place determined by a combination of the four elements: earth, water, air, and fire Straight up or straight down for all things Earth, beyond Earth motion is circular (Sun and Moon continually circle Earth) Any object not in its proper place will strive to get there (stones fall, puffs of smoke rise) Violent Motion: Produced by external pushes or pulls on objects (wind imposes motion on ships) Galileo demolished Aristotle's assertions
Understand that physics is the basic science, fundamental to all other sciences.
Nature of basic things Under bio is chem, under chem is physics (underlies all science) The concepts of physics reach up to these more complicated sciences
State and explain all of Newton's three laws of motion.
Newton' First Law, the law of inertia: an object at rest tends to remain at rest; an object in motion tends to remain in motion at constant speed along a straight line path. The property of objects to resist change in motion is called inertia. Objects will undergo changes in motion only in the presence of a net force. Newton's Second Law, the law of acceleration: When a net force acts on an object, the object will accelerate. The acceleration is directly proportional to the net force and inversely proportional to the mass. Symbolically, a=F/m/ Acceleration is always in the direction of the net force. When object fall in a vacuum, the net force is simply the pull of gravity and the acceleration is g (acceleration due to gravity alone). When objects fall in air, the net force is equal to gravity's pull minus the force of air resistance, and acceleration is less than g. If and when the force of air resistance equals the gravitational force on a falling object, , acceleration terminates, and the object falls at constant speed (called terminal speed) Newton's Third Law, the law of action-reaction: whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. Forces occur in pairs, one action and the other reaction, which together constitute the interaction between one object and the other. Action and reaction always occurs simultaneously and act on different objects. Neither force exists without the other.
Define net force and how it relates to Newton's First Law of Motion.
Newton's First Law of Motion- every object continues in a state of rest or of uniform speed in a straight line unless acted on by a nonzero net force. Net Force: (vector sum of forces acting on an object) combination of all the forces that act on an object The net force influences the motion of an object.
Give examples of third-law force pairs and identify force pairs in various situations.
Newton's Third law: Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. There is always an action and reaction Coparts of a single interaction and that neither force exists without the other Ex. When you walk you interact with the floor. Your feet push against the floor, and the floor pushes against your feet. The two forces occur at the same time (simultaneous). Ex. tires of a car push against the road while the road pushes back on the tires. The road and the tires simultaneously push against each other.
Understand that a non-zero net force is the cause of acceleration and be able to explain the equation relating acceleration, net force and mass. i.e. be able to explain Newton's Second Law of Motion in both words and the equation.
Objects acceleration is proportional to an objects net force If you triple the net force applied, the acceleration triples
Describe the motion of an object thrown straight up until it hits the ground under negligible air resistance.
Once the object is released, object continues moving upward for a time and then comes back down. At the object's highest point, when it is changing its direction of motion from upward to downward, its instantaneous speed is zero. Then it starts downward just as if it had been dropped from rest at that height. During upward part of this motion, object slows as it rises. Slows at the rate of 10 meters per second Same acceleration it experiences as goes downward Instantaneous speed at points of equal elevation in the path is the same whether the object is moving upward or downward Velocities are opposite because going in opposite directions Downward velocities have negative sign, up is positive Whether object is moving upward or downward acceleration is the SAME at all times, 10 m/s^2
Describe spherical aberration in spherical mirrors and how it is eliminated with parabolic mirrors.
Parallel light rays that bounce off the central region of a spherical mirror focus farther away than light rays that bounce off the edges This results in many focal points, which produce a blurry image. To get a clear image, all rays need to focus at the same point. Changing the shape of a mirror from spherical to parabolic solves the problem All light rays focus at the same point and the resulting image is sharp and clear.
Apply the parallelogram rule to find the resultant of a pair of vectors (both pairs of vectors at right angles to each other and pairs that are not at right angles).
Parallelogram Rule: vectors at right angles can be combined into one resultant vector (right definition?) Resultant: the net result of a combination of two or more vectors Vectors: an arrow drawn to scale used to represent a vector quantity Create parallelogram and the resultant is diagonal line in the center (vectors (arrows) are sides of the parallelogram) C= A+ B (vectors) Know the Pythagorean theorem
Identify and explain primary, complementary, additive and subtractive colors.
Primary: primary color for light - any of three primary colors of light from which all colors can be obtained by additive mixing; "the primary colors for light are red, blue, and green" Complementary: Any two colors of equal brightness that, when added, produce the sensation of white light Subtractive primary colors: The three colors of absorbing pigments- magenta, yellow, and cyan (greenish-blue)- that, when mixed in certain proportions, can reflect any other color in the visible-light part of the electromagnetic spectrum Magenta (opposite of green) Cyan (opposite of red) Yellow (opposite of blue) Subtractive primaries are complementary to additive primaries Magenta +green= white= red + blue +green Yellow + blue = white + red + green + blue Additive primary colors: The three colors- red, blue, and green- that when added in certain proportions, produce any other color in the visible light part of the electromagnetic spectrum and can be mixed equally to produce white light Combination of two of the three additive primary colors Red + blue= magenta Red + green= yellow Blue + green= cyan
Define impulse and calculate the impulse given to an object (represented by the letter J) using J = F*t.
Product of force and time In the notes conceptual examples are the car hitting the hay v cement wall
Explain how the trajectory of the projectile depends upon the frame of reference from which it is observed.
Projectile: Motion of an object given initial velocity that then, moves only under the force of gravity Trajectory: The path of a projectile through space Frame of reference: A coordinate system from which motion is viewed How everything is relative and it depends on where you are looking from
Outline the common components of any expression of scientific method
Recognize a question or a puzzle Make a hypothesis Predict consequences of hypothesis Perform experiments or make calculations to test predictions Formulate a general rule that organizes hypothesis, predicted effects, and findings
Why the sky is blue; (511)
Results of selective scattering (excites particles and reemits the particles) of smaller particles than the wavelength of incident light and resonances at frequencies higher than scattered light Tinier the particle, higher the frequency it will re-emit Varies in different locations under different conditions Clear dry day- much deeper blue sky Clear, humid day- beautiful blue sky Lots of dust particles and larger molecules than nitrogen and oxygen in atmosphere- less blue sky with whitish appearance After heavy rainstorm (washing away of airborne particles)- deeper blue sky
Distinguish between the rods and cones of the eye and their functions.
Rods handle vision in low light They predominate towards the periphery of the retina Cones handle color vision and detail They are denser toward the fovea Three types of cones stimulated by low, intermediate, and high frequencies of light
Define science and technology.
Science is concerned with gathering knowledge and organizing it, technology is applied science, used by technologists and engineers for practical purposes- provides tools needed by scientists in further exploration
Be able to discuss different sources of energy and know that the sun is the ultimate source of energy for fossil fuels, dams and windmills.
Solar, nuclear, wind, and hydro
Demonstrate the ability to calculate speed and to solve an equation involving speed, distance, and time for an object in uniform motion.
Speed is the distance covered per unit of time. Speed= distance/ time Ex. Math A cyclist who covers 16 meters in a time of 2 seconds, for example, has a speed of 8 meters per second. Instantaneous speed is the speed at any instant, the speed changes and therefore the distance covered is either more or less depending on the slower or faster speed. Average Speed is the total distance traveled divideda by the time of travel. Average speed= total distance covered/ time interval Total distance covered= average speed X time interval
Describe the properties and uses of spherical mirrors.
Spherical mirrors are used for seeing closer to faces because spherical mirrors make the image enlarged.
Define terminal speed and explain the relationship between it and mass.
Terminal Speed: the speed at which the acceleration of an object terminates because air resistance balances gravitational force The greater the mass the greater the terminal velocity, with the result the heavier object reaches ground first
Explain the law of reflection.
The angle of reflection equals the angle of incidence
Explain the role of mathematics as the language of science.
The equations of science provide compact expressions of relationships between concepts- they show the connections between concepts in nature
Predict the effect of distance on light's illumination.
The greater the area to be illuminated, the less apparent brightness of the bulb becomes (as distance increases, light intensity decreases)
Distinguish instantaneous velocity from average velocity.
The instantaneous velocity is the specific rate of change of position (or displacement) with respect to time at a single point (x,t) , while the average velocity is the average rate of change of position (or displacement) with respect to time over an interval.
Explain in detail the "scientific attitude"
The scientific method inclined toward inquiry, integrity, and humility
Explain the Equilibrium Rule, including the two types of equilibrium (static and dynamic).
The vector sum of the forces acting on an accelerating object equals zero Static Equilibrium: the object is not moving but in equilibrium Equilibrium (not accelerating) Dynamic Equilibrium: the object is moving in equilibrium
Explain the difference between transparent and opaque materials and the reasons they are the way they are.
Transparent materials Electrons or molecules in the glass are forced into vibration Energy in momentarily absorbed and vibrates the electrons in the glass The vibrating electron either emit a photon or transfers the energy as heat Time delay between absorption and re-emission of energy of vibrating electrons results in a lower average speed of light through transparent material Glass is transparent to visible light but not ultraviolet or infrared Opaque materials Absorb light without re-emitting it Vibrations given by light to their atoms and molecules are turned into random kinetic energy- into internal Materials become slightly warmer
.Resolve a given vector into its vector components.
Vector Components: Mutually perpendicular vectors, usually horizontal and vertical, whose vector sum is a given vector. So right angle and use the Pythagorean theorem If vector is up and to the right the arrows need to be going in a similar direction Resolution: the process of determining the components of a vector
Distinguish between a vector and a scalar.
Vector quantity- A quantity that has both magnitude and direction Ex. force Vector- an arrow drawn to scale used to represent a vector quantity Scalar quantity- A quantity that has magnitude but not direction Ex. mass, volume
Explain the difference between vector and scalar quantities.
Vector quantity: a quantity that has both magnitude and direction, such as force Scalar quantity: a quantity that has magnitude but not direction, such as mass and volume
Define velocity and differentiate between speed and velocity.
Velocity- An object's speed and direction of motion Speed- How fast an object moves; the distance traveled per unit of time Velocity combines the ideas of speed and direction of motion Ex. car travels at 60km/h, we know its speed. But if we say the car moved at 60km/h to the north we specify its direction.
Describe the properties of the images formed by plane (flat) mirrors.
Virtual Same size Upright Same distance Same depth in front of as behind Mirror has to be half of your height to see your full body
Demonstrate an understanding of virtual and real images
Virtual (only SEEM to intersect) Where rays converge (to produce a clear image) The virtual image formed by a convex (a mirror that curves outward) is smaller and closer to the mirror than the object When the object is close to a concave mirror (a mirror that curves inward like a "cave"), the virtual image is larger and farther away than the object In either case, the law of reflection applies to each ray Produced by flat mirrors, convex mirrors..... Real Where rays diverge Can be produced by concave mirrors On a screen Concave mirrors bend inward like a cave. These mirrors reflect light rays inward towards a focal point. Images will appear upside down from far away, but very close to the mirror, they will appear right side up and very large. In contrast, concave lenses reflect light rays outwards. The image through a concave lens will always be right side up. Convex mirrors curve outwards and reflect light rays away from the center. Images will appear right side up and smaller than the actual object. Convex lenses, on the other hand, refract light rays in toward a central point. The image seen through a convex lens is upside down when the lens is held away from your face, but the image is magnified and right side up when the lens is held closer to your eye.
Explain shadows, especially of the earth and moon (eclipses)
Vocab with shadow Solar eclipse Due to the size of the sun the rays taper to provide an umbra and surrounding penumbra Lunar eclipse The moon passes completely into the shadow of the Earth
Why water is greenish blue;(514)
Water molecules resonate somewhat in the visible red, which causes red light to be a little more strongly absorbed in water than blue light Red light is reduced to one-quarter of its initial brightness by 15 meters of water Very little red light in the sunlight that penetrates below 30 meters of water When red is removed from white light, the complementary color of red remains: cyan- a bluish green color Ex. The intriguing vivid blue of lakes in the Canadian Rockies is due to scattering The lakes are fed by runoff from melting glaciers that contain fine particles of silt, called rock flour, which remain suspended in water Light scatters from these tiny particles and gives the water its eerily vivid color
Demonstrate an understanding of the formation of color by combining different colors of light.
When mixing all of the additive primary colors (blue, green, red) of light together, they form white Color we see depends on the frequency of the light Lowest frequency is red Highest frequency violet In between those frequencies are the colors of rainbow (OYGBI) Beyond violet, is invisible ultraviolet (cannot see it) The intensity of light from the Sun varies with frequency Yellow- green is most intense part of the spectrum Our eyes have evolved to have maximum sensitivity to this range
Explain what is meant by the expression "all motion is relative"
When we explain the motion of something, we describe the motion relative to something else. Unless stated otherwise, when people discuss the speeds of things in our environment we mean relative to the surface of Earth. Motion is relative. In other words we compare motion to other objects/things on Earth, therefore the motion may be described differently when comparing the speed to different environments. Ex. When walking down aisle of the bus, your speed is relative to the floor of the bus, this speed is likely very different from your speed relative to the road. When saying a car reaches a speed of 300 kilometers per hour, we mean relative to the track.
Explain that scientific measurements are essential to the advanced understanding of a scientific concept
When you cannot measure something and express it in numbers, scientific measurements are not something new but go back to ancient times
Display an understanding that scientific work is energy transferred to or from an object by means of a force acting on the object.
Work:The product of the force and the distance moved by the force in the SAME direction and is the transfer of energy: W=Fd (work= force x distance) Ex. When lifting a load of gravel against Earth's gravity, the heavier the load or the higher it is lifted more work is done. (DOES THIS ANSWER FULL OBJECTIVE?)
Differentiate between work and power, define them, and be able to calculate them in simple problems. Distinguish between scientific and ordinary meaning of work.
Work:The product of the force and the distance moved by the force in the SAME direction and is the transfer of energy: W=Fd (work= force x distance) J= N x m Measured in Joules Scientific references work as a transfer of energy and normal activity just means physical or mental exertion Power:The time rate of work: Power=work/ time Watts = J/S
Apply Pythagorean Theorem to find the resultant of two vectors at right angles to each other.
a^2 + b^2= c^2
Define a ray and give examples of evidence that light in a uniform medium travels in straight lines.
each of the lines in which light (and heat) may seem to stream from the sun or any luminous body, or pass through a small opening. any of a set of straight lines passing through one point. spread from or as if from a central point Shadows are evidence of light travelling in straight lines Hand over a spot, it is completely dark (umbra) under Refraction is another evidence is where light passes from one transparent medium into another
Relate the index of refraction to the speed of light in a medium.
n = c / v ''c" is the speed of light in a vacuum "v" is the speed of light in that substance "n" is the index of refraction According to the formula, the index of refraction is the relation between the speed of light in a vacuum and the speed of light in a substance
Relate Newton's third law to conservation of momentum (as done in class).
picture in study guide
Describe what is meant by support force.
support force: an upward force on an object that is opposite to the force of gravity example: a book on a table compresses atoms in the table, and the compressed atoms produce the support force, when you push down on a spring the spring pushes back on you)
Explain total internal reflection and define the critical angle (and how it applies to fiber optic technology.)
total internal reflection takes place at the boundary between two transparent media when a ray of light in a medium of higher index of refraction approaches the other medium at an angle of incidence greater than the critical angle