Physics OAT
Which is the correct formula for the energy stored in a fully-charged capacitor with Capacitance C when its attached to a battery of voltage V?
1/2CV^2
A person riding at a steady pace on an exercise bicycle generates 40 Watts of power. How long does it take the person to burn off 24,000 Joules of energy.
10 minutes Power = energy/time
A 1 kg mass hangs vertically on a spring with a spring constant of 100 N/m. If the mass is displaced slightly from equilibrium and released, what is the angular frequency of the resulting oscillation?
10 rad/s weight = square root k/m
A force of 25 N pulls three blocks connected by a string on a frictionless surface. What is the tension in the rope between the 4.0 kg block and the 2.0 kg block?
11.1 N - F = ma
What is the total resistance between points X and Y in the circuit diagram below?
12 Ohms - 1/R = 1/R1 + 1/R2 + .....
The pulley in the device below has no mass and is frictionless. The larger mass is 30 kg and the smaller mass is 20 kg. What is the acceleration of the masses?
2 m/s^2 - W = mg for both masses - Calculate net force Mgreater - Msmaller - F = ma (solve for acceleration
The half life of carbon-14 is 5730 years. A fossill is found that contains approximately 1/16th of the carbon-14 that was present when the organism was alive. The approximate age of the fossil is ?
22,920 years - Radioactive decay equation
An 8 kg block slides down an incline 20 m in length with a coefficient of friction of .5. The angle of inclination of the plane is 60 degrees. How much energy is dissipated as friction?
392 J
A 10 kg plastic block is at rest on a flatten wooden surface. The coefficient of static friction between wood and plastic is 0.6 and the coefficient of kinetic friction is 0.5. How much horizontal force is needed to start the plastic box moving?
59 N - Start the box moving then solve for static friction - Keep the box moving then solve for kinetic friction - Static friction = ustatic x N.F. - N.F. = mg
Referring to the circuit shown below, the voltage across R2 is equal to the voltage across which other resistor?
R3 Look at kaptest
If the displacement from the center of oscillation of a vibrating spring is plotted against time, what sort of graph is obtained?
Sinusoidal
Electromagnetic radiation - also known as light - consists of perpendicularly oscillating electric and magnetic fields. Which of the following statements about electromagnetic radiation is untrue?
The "color" of light is determined by its wavelength - Frequency determines lights color
A skydiver jumps out of an airplane at an altitude of 10,000 feet. Given that the force of air resistance on the skydiver is proportional to the square of the skydivers speed, which of the following best describes the skydivers acceleration as a function of time?
The acceleration decreased with time
You throw a baseball straight up near the surface of Earth and it falls back to the ground. Which statement is true about the acceleration of the baseball at the top of its path?
The acceleration is -9.8 m/s^2.
An airplane executes a circular holding pattern while maintaining a constant speed and a constant height above ground. Which of the following best describes the airplanes motion?
The airplane experiences a non zero acceleration
One liter of a monatomic gas is held at a temperature of 200K. Which of the following statements best describes the speed of the atoms of the gas?
The atoms have a distribution of speeds with a typical speed proportional to the square root of the temperature - V = square root 3RT/M
Which statement best explains why water expands when it freezes?
The average distance between the water molecules increases
A real object is placed in front of a spherical convex mirror. The image produced by the mirror is
always virtual and upright - mirror equation
Which of the following devices change chemical energy into electrical energy?
battery
Energy is best described as
being a scalar - vector has a magnitude and a direction - scalar only has a magnitude
Which of the following statements best describes the electrical field shown below.
the field is increasing to the right - electric field = Newtons/Columbs
Which of the following statements about energy is true?
total energy is always conserved in an isolated system
A projectile is fired at an angle of 45 degrees to the horizontal with a speed of 1000 m/s. Which of the following best represents the horizontal component of the velocity of the projectile as a function of time?
velocity time graph straight line in middle - Look at Kaptest
Which of the following correctly expresses a volume of 1,000 cm^3 in m^3?
.001 m^3
A young boy pulls his red wagon down the street by exerting a force on the handle of 2 Newtons at an angle of 30 degrees to the horizontal. What is the acceleration of the wagon in m/s^2 if it has a mass of 10 kg?
.2 cos 30 degrees F = ma or a = F/m
A 200 Kg horse pulls a 500 Kg cart at a constant speed of 2 m/s. What is the total force, in newtons, acting on the cart?
0
Two waves, each of which has an amplitude of A, cross paths. At the point where they cross, the peak of one wave meets the trough of another wave. What is the resulting amplitude at the point where the waves cross?
0 - one at its peak and other trough (minimum) hence A - A = 0 - If waves peaking then A + A = 2A - If waves at a minimum then = -2A
A 100-kg bungee jumper jumps off a bridge, attached to a 20 m bungee cord. After bouncing around for a minute he finally comes to rest. The stretched cord is now 25 m long. What is the spring constant of the bungee cord?
196 newtons per meter - k = Fx
An athletes foot is in contact with a kicked football for 100 milliseconds and exerts a force on the football over a distance of 20 cm. The force starts at 0 N and increases linearly to 2000 N for 50 milliseconds through a distance of 10 cm and then decreases linearly for 50 milliseconds through a distance of 10 cm. What is the average power of the athletes foot while it is in contact with the ball?
2 Kilowatts - W = fd = P = W/t
An object is 20 cm in front of a thin convex lens with a focal point of 10 cm. Where is the image located?
20 cm behind the lens
Two children, Tim and Jill, sit on a seesaw of length 4 meters. Tim weighs 400 Newtons and sits at a position of 1 meter to the left of the fulcrum. When Jill sits at a position of 2 meters to the right of the fulcrum, the seesaw is balanced. What is Jill's weight in Newtons?
200 N Torque equation
A state trooper pursues a vehicle moving at a constant, but unlawfully high, speed and manages to match the speed of the vehicle. If the trooper shoots a radar beam with a frequency of 3 x 10^11 Hz at the speeding vehicle, what is the frequency of the return vehicle?
3 x 10^11 Hz
A 75-kg ice skater moving eastward at 5 m/s collides with a 100-kg skater moving northward at 4 m/s. Anticipating the Collison, they hug each other and produce an inelastic Collison. What is their final speed?
3.1 m/s - calculate momentum of each skater - Find total momentum by using Pythagorean theorem - Solve for V in M (total momentum) = m (combined masses) x V
A sound wave has a frequency of 680 Hertz. If the distance between adjacent wave crests is .5 meters, then what is the wave speed in m/s?
340 v = f x wavelength
The masses of four different objects taken with different scales were 23.04 g, 7.12g, .0088g, and 5.423g. What is the total mass of all four objects to the proper number of significant digits? (Start of practice test 1)
35.59
An object experiences an acceleration of 5 m/s^2 when under the influence of a 20-Newton force. What is the mass of the object?
4 kg F = ma
A perfectly circular track has a circumference of 400 meters. A runner goes around the track in 100 seconds instead of her usual time of 80 seconds because a leg cramp causes her to stop running for 20 seconds. What is her average speed?
4 m/s - Speed = distance/time
The center of a circular aquarium window with a radius 1 meter and is 14 meters below the surface. What is the force of the water at this depth pushing on this window? The density of water is 1000kg/m^3
4.3 x 10^5 newtons - P = pgh - P = F x A (piR^2)
An airplane has a velocity with a component of 400 miles/hr to the east and 400 miles/hr to the north. What is the speed of the airplane?
400square root of 2 m/hr - Velocity = displacement/time
In musical instruments with two open ends, the first harmonic fits one-half wave inside the tube. The second harmonic fits 1 full wave in the tube. The third harmonic fits 1.5 full waves in the tube. An organ pipe, open at both ends, has a length of 1.2 meters. What is the frequency of the third harmonic? The speed of sound is 340 meters per second.
425 Hz - wavelength = length(m)/ waves - Wave equation: v =wavelength(f)
The diagram below shows a force F pulling a box up a ramp against the force of friction and the force of gravity. Which of the following diagrams correctly includes vectors representing the normal force, the force of gravity and the force of friction?
A - Look at diagram on pretest #2
Which of the following statements is not a principle used in constructing ray diagrams to show the creation of images using a thin convex lens?
A ray that strikes the surface of a lens follows Snells Law of refaction
In the 19th century, James Clerk Maxwell calculated the speed of light in a vacuum from the proportionality constants used in electrostatics and magnetism. Which of the following relationships correctly identifies how light moves in a vacuum?
All frequencies of light travel at the same speed in a vacuum.
Which of the following statements best explains what is meant by the phase of a wave?
An angle indicating he waves cycle instantaneous location - height and length measured in m not radians - wave fluctuates between 0 and 2pi radians
When is the potential of a point charge with respect to a dipole equal to 0 volts per coulomb?
At an infinite distance from the dipole
Two rays parallel to the optical axis of a concave mirror are incident upon the mirror. Where do the two rays intersect?
At the focal point
Which of the following I-V curves displays a material that has an increased resistance with increased current?
B graph which is increasing reversely Look at Kaptest
Two charges, q1 and q2, are a distance x apart from each other. if q2 is doubled and x is doubled, what is the change in the electrostatic force F between the charges?
F is halved
A magnetic field is directed into this page and an electron is moving from left to right as indicated in the diagram below. In which direction will the electron move when it enters the magnetic field?
It will curve downward
The relation between the heat absorbed by a body and its change in temperature is given by Q=mc x change T. What are the following units of C?
Joules/ (kgxK)
A school nurse measures the height of every boy in a school with 1000 pupils and determines that the average height is 1.64 meters with a standard deviation of 0.05 meter. Which of the following statements is true?
None of these statements may be made conclusively - You do not know the exact distribution of heights so none of the options
A negatively charged plastic rod is brought near an uncharged ball which is made from an insulating material. Which of the following best describes the effect of the rod on the ball?
The ball is attracted to the rod
Which statement correctly states the work-energy theorem?
The change in Kinetic energy of an object is equal to the work done on an object. - W = ChangeKE (derived from newtons second law)
Which of the following statements about a solid metal sphere with a net charge is true?
The charge will be distributed uniformly at the surface of the sphere
Which of the following is true of an electric dipole?
The charges are equal in magnitude and have opposite signs
Two beams of light with the same phase and wavelength travel different paths and arrive at the same point. If maximum constructive interference occurs at this point, which of the following statements is true?
The lengths of the paths differ by an integral number of wavelengths
Which of the following statements explains what causes a rainbow?
The speed of light in water depends on its wavelength
Suppose a moving railroad car collides with an identical stationary car and the two cars latch together. Ignoring friction, and assuming no deformation on impact, which of the following statements is true?
The speed of the first car decreases by half - Collison elastic when neither object loses KE
A book rests on a table top. Which of the following best describes the reaction force to the downward force of gravity on the book?
The upward force on the earth exerted by the book
A ball is thrown vertically upward. Which of the following best describes both the velocity and acceleration of the ball at its highest point?
The velocity is zero and acceleration is 10 m/s^2
Which of the following is a vector quantity? (Start of practice Test #2)
Velocity - Vector has both a magnitude and direction
A block of weight W is at rest on a plane inclined at an angle theta with respect to the horizontal. What is the force of friction on the block?
W sin (theta)
Current in an electrical circuit is normally measured in amperes. Which of the following does not represent an alt. way of expressing units of current?
Watt-volts
The strong force between two adjacent protons in the nucleus is
attractive
On a cold winters morning, a barefoot person places one foot on a tile floor and the other foot on thick carpeting and notices the foot on the tile floor feels colder. The reason is
that the tile has a higher thermal conductivity than the carpet
When a solid cube is submerged upright in a liquid, the liquid exerts a pressure of on?
the top, bottom, and sides of the cube
A teacher pulls a box across the floor at a uniform speed. He pulls it with a spring scale showing that the force of kinetic friction is 2 newtons. How much total work is done in moving the box 5 meters?
0 Joules - Uniform speed then net force on box is 0 Newtons
A homemade generator rotates at a constant frequency and produces an alternating current with a maximum voltage of 40 volts. It is connected to a resistor of 20 Ohms. What is the average current that flows through the resistor?
0 amperes - I = V/R = 2 amps - But bc it is an alternating current it will flow from -2 to +2 making the average current 0 amps.
Two 5 kg objects moving with equal and opposite velocities of magnitude of 10 m/s collide and stick together. What is the speed of the resulting 10 kg object just after the collision?
0 m/s
Two tuning forks have a frequency of 500 Hz and 504 Hz. and the same amplitude. How much time is there between beats?
0.25 seconds - 504 - 500 = 4 beats per second (Hz) - 1/f = T - 1/4 = .25 seconds
Substance A has a density of 5.0 kg/m^3 and substance B has a density of 4.0 kg/m^3. What is the ratio of volume A to volume B when the masses of the two substances are equal?
0.80 - 4/5 = .80 - Density = m/v
A ball is released from a certain height along a frictionless track that does a loop-the-loop. The loop-the-loop part of the track is a perfect circle of radius R. At what height above the ground must the ball be released from in order to not fall off the track when it gets to the top of the loop-the-loop?
5R/2 - PE = mgh - KE = 1/2(mv)^2 - conservation of energy = mgh = 1/2mv^2 + mg(2R) - h = 1/2R + 2R = 5/2R
Which of the following is the correct definition of a conductor?
A material that contains moveable electrical charges
A pair of eyeglasses consists of steel wire frames and lenses made from ordinary glasses. The coefficient of linear expansion of steel is 11 x 10^-6(C degrees)^-1 and that of ordinary glass is 9 x 10^-6(C degrees)^-1. If the temperature rises by 20 degrees Celsius then?
Both the frames and the lenses will expand but the frames will expand more.
A cube of substance is 5 cm on each side. It is placed in a pressure chamber where the pressure on each surface is 3.0 x 10^7 N/m^2, causing the density of the cube increases by .01%. Which of the following theories is used to describe this?
Bulk modules - elastic modules = ratio of stress to strain for an object - Young modules = elasticity and length of object - Shear modules = elasticity of shape and stress that's applied perpendicular to its surfaces
Consider the two vectors below: Which vector best represents the vector obtained by subtracting A from B (B - A)?
C - Look at diagram
In the expression below, y is in newtons and v is in m/s. Which of the following correctly identifies the units of c and d? v = c x sin(y/d)
C is in m/s D is in newtons
The diagram below shows two batteries connected in series to a resistor. What is the direction of current flow?
Cant be determined from the info given - don't know voltage of batteries
Which type of aberration does not occur with concave spherical mirrors?
Chromatic aberration = does not occur bc this concernes lens not mirrors - Spherical aberation = occurs bc focal point of the mirror changes slightly as you move away from the center - Astigmatism = occurs bc incident rays are not parallel - Distortion = concerns magnification and occurs in both mirrors and lens
Suppose you have a pipe of length (L) and radius (r), and a liquid with viscosity (n). You also have a sensor to detect the liquids flow rate, which measures the volume of liquid passing through the pipe per second. If you want to increase the flow rate, what changes to L, r, and n should you make? Assume that the pressure differential remains constant.
Decrease L, increase r, and decrease n - Increase flow rate = reduce length, make pipe wider (r) , and low viscosity (n)
When light from a single source strikes two slits, alternating bright and dark lines appear on a screen on the far side. What is the best explanation for this phenomenon?
Diffraction and interference - Chromatic aberration = blurring through a lens due to different colors of light - Doppler Shift = Affects wavelength of light from moving sources - Total internal reflection = 100% reflection of light at the boundary between certain materials
Ultrasound imaging, which is used for various medical procedures, including imaging pregnant women, is based on which of the following principles?
Echolocation = sound waves bounced off objects and returning sound waves are used to create an image - Doppler effect = refers to the changing pitch of sound for objects that are moving towards or away from you - Spectrum of sounds has three areas: Infrasonic, audible, and ultrasonic
Which off the following phenomena implies that light consists of specific quanta?
Emission of light - ultraviolet catastrophe = frequency distribution of light emitted by a blackbody - Threshold frequency = refers to photoelectric effect (stability of atoms is a quantum phenomena) indirectly connected to the light quanta
Specular reflection might come occur on a surface like a mirror, while diffuse reflection might might occur on a wooden tabletop. Which of the following statements best describes the difference between specular and diffuse reflection?
For diffuse reflection, surface irregularities are large compared to the wavelength of visible light
Which law says the number of electric field lines passing through an imaginary surface is proportional to the net charge inside the surface?
Gauss Law = concerns electric field lines - Coulumbs law = attrative force between any two charged particles - Faradays law = creation of electric fields from moving magnetic fields - Bio-Savart law = concerns the creation of magnetic fields from moving charges
A radar gun sends out a pulsed beam of microwave radiation to measure the speed of cars using the Doppler effect. The pulsed beam bounces off the moving car and returns to the radar gun. For a car that's moving away from the radar detector, which of the following statements about the pulsed beam are true? I. It returns with a longer wavelength II. It returns with a shorter wavelength III. It returns with a higher frequency
I. only - Doppler effect shoes that light/radiation from an object moving away has a longer wavelength - c = vf - Car moving towards radar would have a shorter wavelength
Consider the following statements about Newtons Law: I. A Newton is a fundamental unit II. Mass and acceleration are inversely related when the force is constant III. Newtons first law can be derived from Newtons second law IV. Newtons second law can be derived from the universal law of gravity Which of the following statements are true?
II and III only - defined by fundamental units: N = kg x m/s^2 - Newtons second law cannot be derived from the universal law of gravity - Newtons first law = an object will stay at rest unless a force acts upon it - Newtons second law = F = ma - Newtons third law = every force has an equal and opposite reaction
A space station is revolving in a circular orbit around Earth. Consider the following three statements: I. The center of mass of the space station is necessarily located at its geometric center II. The center of mass is moving at a constant velocity III. The center of mass of the space station is moving at a constant speed Which of the following statements are true?
III. is true
Conservative forces are forces that do not lose energy to processes like friction and radiation and where the total mechanical energy is conserved. Which statement best explains why the work done by a conservative force on an object does not depend on the path the object takes?
If a force is conservative, any component of the force is equal to the change in a potential energy divided by the change in position
A 6-megaohm resistor is connected in series with a 5.0-microfarad capacitor and fully charged with a 3-volt battery. The battery is disconnected and the capacitor is connected directly to the resistor. How long will it take for the capacitor to fully discharge?
Infinite time
A capacitor is connected in series to a battery and a resistor. The battery is disconnected after the capacitor is charged and replaced by a battery with a greater electromotive force, causing the capacitor to gain additional charge. After the capacitor has fully charge again, which of the following statements is true about the capacitance of the circuit?
It has remained the same
A cube of aluminum is placed at the bottom of a deep ocean where the pressure is over 20 atmospheres. What happens to the density of the cube?
It increases slightly - Density increases at bottom of ocean
An object with a net charge is brought into the vicinity of an object with a net charge of zero Columbus. Which statement describes the electrostatic force between the two objects?
It is an attractive force
A ray of light traveling in a vacuum (n=1) is incident upon a glass plate (n=1.3). It hits with an angle of incidence of 45 degrees. If the angle of incidence increases to 50 degrees, what is the new angle of refraction?
It is below 45 degrees - angle of refraction is about 36 degrees - Snell's Law: n1sintheta1 = n2sintheta2
A submarine sits underwater at a constant depth of 50 meters. Which of the following is true about the submarines buoyant force?
It is equal to the submarines weight
Two unequal masses are balanced on a fulcrum using a massless bar, as shown below. If both masses are shifted towards the fulcrum so that their distances from the fulcrum are one-half the original distance, what happens to the masses?
The masses will remain balanced
A circuit consists of a battery and a resistor. An ammeter is used to measure the current in the circuit and is connected in series to the circuit. Which of the following is true?
The current flowing in the resistor decreases - Presence of ammeter reduces current to resistor so it the current will decrease
A beam of light with wavelength 6 x 10^-7 m is incident on a pair of narrow and closely spaced slits. The resulting pattern, seen on a screen located 1 m from the slits, consists of a series of bright and dark regions. Which of the following reasons best describes the reason for the dark regions?
The dark places are the regions where the two light beams are out of phase by one half of a wavelength.
Which of the following best describes how a rocket lifts off of a launching pad?
The downward momentum of the exhaust gases results in the upward momentum of the rocket
The air passing over an airplane's wing is considered an irrotational fluid flow. Which of the following statements correctly describes the concept of irrotational fluid flow?
The fluid does not have any rotating points, whirlpools or eddies - Steady flow describes all particles having the same velocity as they pass a particular point - Rotational flow includes vortex motion, whirlpools, and eddies - fluid flows not straight line bc pipes may be curved
In an amusement park ride, you stand on the floor of a cylindrical ring with your back touching the wall. The ring begins to rotate, slowly at first, but then faster and faster. When the ring is rotating fast enough, the floor is removed. You do not slide down but remained pressed against the wall of the ring. Which is the best explanation for why you don't fall down?
The force of friction between the wall and your body is greater than your weight. - Centripetal force pushes you towards the center of the ring not the wall
A box with a weight of 10 newtons is resting on a table, which is resting on the ground. In the context of newtons third law, if we consider the force of the box on the table to be the action force, which of the following statements is true?
The force of the table of the box is the reaction force
Which of the following statements about the image created by a magnifying glass is true?
The image may be right side up or upside down, depending on the location of the object. - magnifying class convex lens
An object is placed a certain distance away from a convex spherical mirror. Which of the following statements is true?
The image will be smaller and right side up -> Review concave/convex properties
A beam of light goes from a piece of glass (nglass = 1.5) into the surrounding air (nair = 1) at an angle of incidence of 20 degrees. Which of the following best describes the behavior of the beam of light in passing through the interface?
The light beam is bent away from the normal to the interface
Which of the following statements is true about the acceleration of a simple pendulum?
The magnitude of the acceleration is at a maximum when the bob is changing directions - At the bottom acceleration is zero since Tension = weight - At the top (changing direction) acceleration and net force is the greatest
bobsled tracks are flat when they are going straight, but when there is a turn, the track is angled(banked) to create a centripetal force. Assuming no friction, the banking angle is theta, the radius of curvature is r, and the maximum speed the bobsled can have without moving off the track is v. If the radius of curvature is doubled and the banking angle remains the same, which of the following statements is ture?
The maximum speed is 1.4 v. - Centripetal force: F = m(v^2/r)cos(theta) - radical 2 = 1.4
Which of the following is true about a diffraction grating?
The more slits per inch, the greater amount of destructive interference
What does it mean when someone says that electric charge is conserved?
The net charge of an isolated system remains constant
Two positive charges of magnitude of 1 and 2 C are separated by a distance of 1 mm. If the distance between the charges are decreased to .5 mm, then what effect does this have on the force between them?
The new force is 4 x the original force F = kq1q2/r^2
An object with a density of 2.2 g/cm^3 is dropped into a container filled with a liquid of density 2.1 g/cm^3. Which of the following best describes the state of the object?
The object sinks to the bottom of the container
impulse is measured as the change in an objects momentum. Which statement is correct about the impulse on a ball rolling down a hill.
The objects impulse increases - impulse = change in objects mometum (mv) kgx m/s
A large metal storage tank is completely filled with crude oil. Which of the following best describes the outward pressure on the wall of the container at a depth of one half of the height of the tank?
The outward pressure equals the fluid pressure at that depth.
A plastic comb is used to comb someone's dry hair and acquires a large positive charge. The comb is brought close to a small bit of uncharged paper lying on a table. Against the force of gravity, the bit of paper jumps up and sticks to the comb. What is likely to happen next?
The paper will acquire a positive charge and be repelled by the comb
An electron is moving in a straight line. Another particle is moving in a straight line parallel to the path of the electron but in the opposite direction. Initially the electron and particle are far apart, but get closer together. When the two particles are in the vicinity of one another, they experience an attractive magnetic force. Which of the following is a correct inference from this fact?
The particle is positively charged
In resonance, small vibrations can produce a larger standing wave that becomes stronger than the original vibrations, assuming the vibrations are at the right frequency to generate resonance. If a pendulum is vibrated at a resonance frequency, what would you expect to happen?
The pendulum will swing higher
An electric field is pointing from south to north. If a dipole is placed in the field, how will the dipoles orientation change?
The positive charge will be on the northern side and the negative charge will be on the southern side
Suppose your actual weight is 150 pounds and you weigh yourself with an analog scale and get a reading of 152.2 pounds. You repeat the measurement twice more and get 152.1 pounds each time. Which of the following statements is true?
The systematic error is 2.1 pounds
The human eye contains a thing converging lens whose focal length is adjusted by the ciliary muscles to produce a focused image on the retina which is at a fixed distance from the lens. With age, the minimum focal length attainable increases. What effect can this have on an aging persons vision.
This person can have difficulty clearly seeing close objects
How is light created in the core of the sun?
fusion reactions
