Physics 1401 Final Exam Review (Chapters 4-18)
The Second Law of Thermodynamics
(Heat Flow) When objects of different temperatures are brought into thermal contact, the spontaneous flow of heat that results is always from the high-temperature object to the low-temperature object. Spontaneous heat flow never proceeds in the reverse direction. More restrictive than the first law; it says that of all the processes that conserve energy, only those that proceed in a certain direction actually occur.
Charle's Law
(Known as the law of volumes) An experimental gas law that describes how gases tend to expand when heated. The law states that if a quantity of gas is held at a constant pressure, there is a direct relationship between its volume and the temperature, as measured in degrees Kelvin. Examples: 1. A helium Baloon on a cold day: Step outside with a helium balloon on a chilly day and chances are, the balloon will crumble. Once you get back into the warm, however, the balloon will return to its original shape. In accordance with Charles' Law, this is because, a gas, in this case, helium, takes up more space when it is warm. 2. A hot air balloon: A torch is used to heat the air molecules inside the balloon. The molecules move faster and disperse within the space. The gas inside the balloon takes up more space, becoming less dense than the air surrounding it. As such, the hot air inside the balloon rises because of its decreased density and causes the balloon to float. 3. Your car tires losing pressure when its cold outside.
Elastic Deformation
A change in shape of a material at low stress that is recoverable after the stress is removed. A temporary shape change that is self-reversing after the force is removed, so that the object returns to its original shape
Tangential Acceleration is due to what?
A change in speed
Centripetal Acceleration is due to what?
A change in the direction of motion
Restoring Force
A force acting opposite to displacement to bring the system back to equilibrium, which is its rest position. The force magnitude depends only on displacement, such as in Hooke's law.
A helium balloon in an accelerating car (Archimedes Principle and Buoyancy)
A helium balloon in a moving car. During a period of increasing speed, the air mass inside the car moves in the direction opposite to the car's acceleration (i.e., towards the rear). The balloon is also pulled this way. However, because the balloon is buoyant relative to the air, it ends up being pushed "out of the way", and will actually drift in the same direction as the car's acceleration (i.e., forward). If the car slows down, the same balloon will begin to drift backward. For the same reason, as the car goes round a curve, the balloon will drift towards the inside of the curve.
Bulk Modulus
A measure of how resistant to compressibility that particular substance is. Experiments show that the pressure difference required to cause a given change in volume is proportional to that change in volume and inversely proportional to the initial volume of the object.
Intensity Level
A measure of relative loudness
Young's Modulus
A measure of the ability of a material to withstand changes in length when under lengthwise tension or compression. Sometimes referred to as the modulus of elasticity, it is equal to the longitudinal stress divided by the strain.
Torque
A measure of the force that can cause an object to rotate about an axis. The tendency for a force to cause a rotation increases with the distance, r, from the axis of rotation to the force Takes into account both the magnitude of the force, F, and the distance from the axis of rotation, r.
Adiabatic Processes
A process in which no heat flows in or out of a system. Can occur when the system is thermally insulated, or in a system where the change in volume occurs rapidly. Example: The compression of a gas within a cylinder of an engine is assumed to occur so rapidly that on the time scale of the compression process, little of the system's energy can be transferred out as heat to the surroundings.
Torricelli's Law
A simplified method of estimating the velocity of a fluid passing through an open orifice under static pressure.
Bernoulli's Equation
A statement of the conservation of energy principle appropriate for flowing fluids. The qualitative behavior that is usually labeled with the term "Bernoulli effect" is the lowering of fluid pressure in regions where the flow velocity is increased. Also thought of as energy conservation per volume for a fluid
Overdamping
A system that also relaxes back to equilibrium with no oscillations, but more slowly than in critical damping.
Simple Harmonic Motion
A type of periodic motion that occurs when the restoring force is proportional to the displacement from the equilibrium. Occurs when a system's restoring force is proportional to the displacement from equilibrium. Oscillatory motion where the net force on the system is a restoring force.
Transverse Wave
A type of wave where the displacement of individual particles is at right angles to the direction of propagation of the wave Examples: Light Waves, Radio Waves
Longitudinal Wave
A type of wave where the displacement of individual particles is parallel to the direction of propagation of the wave. Example: Sound
Harmonic Wave
A wave on the string will have the shape of a sine or a cosine function
Standing Waves
A wave that oscillates with time, but remains fixed in its location. It's in this sense that the wave is said to be "standing." Are often a result of constructive interference of a wave with itself.
Damped Oscillations
Systems in which mechanical energy is lost to other forms eventually come to rest at the equilibrium position.
Buoyant Force
The net upward force exerted by a fluid on any object it surrounds.
What is the relationship between normal force and gravitational force?
The normal force on the object is equal but in opposite direction to the gravitational force applied on the object
Viscosity
The tendency to resist flow; occurs when a fluid flowing past a stationary surface experiences a force opposing flow.
Period of Rotation
The time required to complete one full rotation. If the angular velocity is constant, T is related to v T = 2pi/w
Thermal Energy
The total amount of energy in a substance—the sum of all of its kinetic and potential energy—is referred to as its internal energy, or thermal energy. Refers both to the random motion of its particles (kinetic energy) and to the separation and orientation of the particles relative to one another (potential energy).
The Harmonic Wave Function
The wave function depends on BOTH time and position, and repeats whenever the position increases by the wavelength, or time increases by the period, T.
Isotherms
Constant temperature curves for an ideal gas.
Phase Equilibrium
Exhibited by a substance when a substance has two or more phases that coexist in a stable fashion. Example: pg. 597
Kinetic Friction
Experienced by surfaces that are in contact and moving relative to one another. The force of kinetic friction is given by ƒk = mkN In this expression, mk is the coefficient of kinetic friction and N is the magnitude of the normal force.
Static Friction
Experienced by surfaces that are in static contact. The maximum force of static friction is given by ƒs,max = msN In this expression, ms is the coefficient of static friction and N is the magnitude of the normal force. The force of static friction can have any magnitude between zero and its maximum value.
Radiated Power
Experiments show that objects absorb radiation from their surroundings according to the same law, the Stefan-Boltzmann law, by which they emit radiation. If the object's temperature is greater than its surroundings, it radiates more energy than it absorbs and Pnet is positive. On the other hand, if its temperature is lower than the surroundings, it absorbs more energy than it radiates and Pnet is negative. When the object has the same temperature as its surroundings, it is in equilibrium and the net power is zero.
Conservative Force
Forces that conserve the mechanical energy of a system. Thus, in this system the total mechanical energy remains constant. This force does zero total work on any closed path. In addition, the work done by a conservative force in going from point A to point B is independent of the path from A to B. Ex: Gravitational force, spring force
Examples of Periodic Motion
Heartbeats, orbit, the ticking of a clock, the movement of a child on a swing
Radiation
Heat exchange due to electromagnetic radiation, such as infrared rays and light. Examples: Heat from the sun warming your face, Heat from a lightbulb, Heat from a fire
Convection
Heat exchange due to the bulk motion of an unevenly heated fluid. The movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink, which consequently results in the transfer of heat. Examples: An old-fashioned radiator (creates a convection cell in a room by emitting warm air at the top and drawing in cool air at the bottom), A convection oven
The Right-hand Rule
If a hand is curled around the axis of rotation with the fingers pointing in the direction of the force, then the torque vector points in the direction of the thumb.
The Zeroth Law of Thermodynamics
If object A is in thermal equilibrium with object C, and object B is separately in thermal equilibrium with object C, then objects A and B will be in thermal equilibrium if they are placed in thermal contact.
Critical Damping
In a system with critical damping, the system relaxes back to equilibrium with no oscillations in the least possible time.
Newton's First Law of Motion
Law of Inertia this law states that every object will remain at rest or an object moving in uniform motion will remain in motion unless acted upon by an external force. The key point here is that if there is no net force acting on an object (if all the external forces cancel each other out) then the object will maintain a constant velocity. If that velocity is zero, then the object remains at rest. If an external force is applied, the velocity will change because of the force
Conservation of Momentum
Momentum is conserved when the net force acting on a system is zero.
Oscillatory Motion
Repeated back and forth movement over the same path about an equilibrium position, such as a mass on a spring or pendulum.
Doppler Effect for a Moving Source
Sound waves from a moving source are bunched up in the forward direction, causing a shorter wavelength and a higher frequency. The minus sign is used when the source moves toward the observer, and the plus sign when the source moves away from the observer. The speed v refers to the speed of sound, and the speed u refers to the speed of the source of the sound.
Doppler Effect for a Moving Observer
Sound waves from a stationary source form concentric circles moving outward with a speed v. To the observer, who moves toward the source with a speed u, the waves are moving with a speed v + u. The appropriate signs are obtained by using the plus sign when the observer moves toward the source, and the minus sign when the observer moves away from the source.
The First Law of Thermodynamics
States that heat is a form of energy, and thermodynamic processes are therefore subject to the principle of conservation of energy. This means that heat energy cannot be created or destroyed. The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another but can be neither created nor destroyed
Boyle's Law
States that the pressure of a gas varies inversely with volume - as long as the temperature and the number of molecules is held constant. Examples: 1. Applying pressure to an inflated balloon (With the increase in pressure, the volume will also decrease accordingly; the balloon will burst at a breaking point.) 2. Your ear's popping on an airplane. (With an increase in altitude, there is a pressure change from high to low. This causes a variation of air pressure inside and outside the eardrums. In the ears, the air in the airspace of the ears will increase in volume, causing the ears to pop due to the eardrums feeling the strain.)
Nonconservative Force
These forces convert mechanical energy into other forms of energy, or convert other forms of energy into mechanical energy. The work done by a nonconservative force on a closed path is nonzero. The work is also path dependent. Ex: Friction, tension in a rope, cable, etc., Forces exerted by a motor, Forces exerted by muscles
Newton's Law of Universal Gravitation
This law states that all objects in the universe attract all other objects in the universe by way of the gravitational interaction. It is in this sense that the force law is called "universal."
Hooke's Law
This law states that the force exerted by an ideal spring stretched by the amount x is proportional to the stretch. Specifically, Fx = -k
Adiabatic Heating
When a piston that fits snugly inside a cylinder is pushed downward rapidly, the temperature of the gas within the cylinder increases before there is time for heat to flow out of the system. Thus, the process is essentially adiabatic. As a result, the temperature of the gas can increase enough to ignite bits of paper in the cylinder. in a diesel engine, the same principle is used to ignite an air-gasoline mixture without a spark plug.
Linear Expansion
When an object of length L0 is heated by the amount ∆T , its length increases by ∆L
Shear Deformation
When equal and opposite forces are applied to the top and bottom of a book, it results in a shear deformation. This changes the shape of a solid. The amount of deformation is proportional to the force F and the thickness of the book L0, and inversely proportional to the area A.
Newton's Third Law of Motion
This states that for every action (force) in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exerts an equal force on object A. Notice that the forces are exerted on different objects. this law can be used to explain the generation of lift by a wing and the production of thrust by a jet engine.
Periodic Motion
This type of motion repeats after a definite length of time The period, T, is the time required for a motion to repeat: T = time required for one cycle of a periodic motion The frequency, ƒ, is the number of oscillations per unit time. Equivalently, ƒ is the inverse of the period: ƒ = 1/T ** 1/2ƒ = 2T**
Period
Time required for an entire cycle
Constructive Interference
When they combine, the resulting pulse has an amplitude equal to the sum of the amplitudes of the individual pulses. When two positive pulses combine to give a larger amplitude
Specific Heats vs. Latent Heats
When you solve problems involving specific heats and latent heats, recall that specific heats give the heat related to a change in temperature in a given phase, and latent heats give the heat related to a change in phase at a given temperature.
Impulse
a force acting briefly on a body and producing a change in momentum.
Newton's Second Law of Motion
this law explains how the velocity of an object changes when it is subjected to an external force. The law defines a force to be equal to change in momentum (mass times velocity) per change in time
Kepler's 3 Laws of Orbital Motion
1) The orbits of the planets are ellipses, with the sun at one focus. 2) Planets sweep out equal areas in equal times. 3) The period of a planets orbit, T, is proportional to the 3/2 power of its average distance from the sun, r:
1) What is Torque analogous to? 2) What is The Moment of Inertia analogous to? 3) What is Angular Acceleration analogous to?
1) Torque is analogous to Force 2) The Moment of Inertia is analogous to Mass 3) Angular Acceleration is analogous to Linear Acceleration
Speed of a Wave (two defining characteristics that determine the speed of a wave)
1. The tension in the string 2. The mass of the string
An object is undergoing Simple Harmonic Motion if:
1. the acceleration of the object is directly proportional to its displacement from its equilibrium position. 2. the acceleration is always directed towards the equilibrium position.
Constant Volume Processes
Adding heat to a system of constant volume: Heat is added to a system of constant volume, increasing its pressure from Pi to Pf. since there is no displacement of the walls, there is no work done in this process. Therefore, W = 0 and the change in internal energy is simply equal to the heat added to or removed from the system, ∆U = Q.
Thermal Equilibrium
After some time in thermal contact, the transfer of heat ceases.
Pascal's Principle
An external pressure applied to an enclosed fluid is transmitted unchanged to every point within the fluid.
Archimedes Principle
An object immersed in a fluid experiences an upward buoyant force equal to the weight of the fluid displaced by the object. This principle applies to an object of any size and shape, and to any type of fluid. The fact that the pressure in a fluid increases with depth leads to a net upward force on any object that is immersed in the fluid. This upward force is referred to as a buoyant force. The magnitude of the buoyant force is equal in magnitude to the weight of fluid displaced by the object. It applies equally well to objects that are completely immersed, partially immersed, or floating. The warm air inside a hot-air balloon is less dense than the surrounding cold air, so that the buoyant force on the balloon (from the displacement of the cold air) is larger than its weight, and the balloon rises into the sky. Hydrogen or helium-filled balloons work on the same principle.
Torque and Angular Acceleration
Angular Acceleration is directly proportional to the torque, and inversely proportional to the moment of inertia
Angular Frequency
Angular frequency is associated with the number of revolutions an object performs in a certain unit of time
The Kinetic Theory of Gases
Describes a gas as a large number of submicroscopic particles (atoms or molecules), all of which are in constant rapid motion that has randomness arising from their many collisions with each other and with the walls of the container.
Intensity
Determines the loudness of a sound by the amount of energy that passes through a given area in a given time
Inelastic Collisions
During this type of collision, momentum is conserved, but the kinetic energy is not conserved. In this type of collision, the final kinetic energy is different from the initial kinetic energy. The kinetic energy is usually less after a collision, but it can also be more than the initial kinetic energy.
Underdamping
In an underdamped case, a system of mass m and damping constant b continues to oscillate as its amplitude steadily decreases with time. The decrease in amplitude is exponential:
Elastic Collisions
In this type of collision, the final kinetic energy is equal to the initial kinetic energy. In this type of collision, momentum and kinetic energy are conserved.
The Moment of Inertia
It is a scalar value which tells us how difficult it is to change the rotational velocity of the object around a given rotational axis. The rotational inertia of an object depends on its mass. It also depends on the distribution of that mass relative to the axis of rotation.
Angular Momentum
It is the quantity of rotation of a body, which is the product of its moment of inertia and its angular velocity. It measures the momentum of a body in rotational motion
Static Equilibrium
Occurs when both the net force and the net torque acting on it are equal to zero.
When is an object in Thermal Contact?
Occurs when heat can flow between two objects.
Coordinate system on an incline
On an incline, align one axis (x) parallel to the surface, and the other axis (y) perpendicular to the surface. That way the motion is in the x direction. Since no motion occurs in the y direction, we know that ay = 0
Physical Pendulum
One in which the mass is not concentrated at a point, but instead is distributed over a finite volume.
Young's Modulus and Tensile Strength
Tensile strength is the value of the maximum stress that a material can handle. This is the limit between plasticity zone and rupture zone Tensile Modulus - or Young's Modulus alt. Modulus of Elasticity - is a measure of stiffness of an elastic material. It is used to describe the elastic properties of objects like wires, rods or columns when they are stretched or compressed A tensile test is an experimental measure, where you try to elongate an object while measuring the strength you are using to do so. The elongation process is made with a constant speed until we reach the breaking point. This gives us everything we need to draw a force curve based on the elongation. Thanks to those values, we are then able to deduce the elasticity modulus of the material, and its elongation at the rupture point Example: Stretching a rubber band
Radian
The angle for which the arc length on a circle of radius r is equal to the radius of the circle.
Angular Position
The angle, theta, that a line from the axle to the spot makes with a reference line.
Angular Velocity
The average rate at which an object rotates in a circular path. The rate of change of angular position.
Hohmann Transfer
The basic maneuver used to send spacecraft such as the Mars lander from Earth's orbit about the Sun to the orbit of Mars. To move to a larger orbit, you must fire your accelerating rockets twice. The first firing puts you into an elliptical orbit that moves farther from the Earth. After the second firing you are again in a circular orbit. This simplest type of orbital transfer, requiring just two rocket burns, is referred to as a Hohmann transfer.
The Doppler Effect
The change in pitch, due to the relative motion between a source of sound and the receiver
Super Position
The combination of two or more waves to form a resultant wave
Shear Modulus
The constant of proportionality in shear deformation; the shear modulus is large in magnitude, meaning that most solids require a large force to cause even a small amount of shear.
Wavelength
The distance over which a wave repeats
The Stefan-Boltzmann Law
The energy radiated per time by an object - that is, the radiated power, P, - is proportional to the surface area, A, over which the radiation occurs. It also depends on the temperature of the object.
Heat
The energy that is transferred between objects because of a temperature difference.
Conduction
The flow of heat directly through a physical matter. Heat flows through a material with no bulk motion. The heat flows as a result of the interactions of individual atoms with their neighbors. Examples: Touching a stove and being burned, ice melting in your hand
Rules of Kinetic Friction
The force of kinetic friction between two surfaces is: 1. Proportional to the magnitude of the normal force, N, between the surfaces: ƒk = mkN 2. Independent of the relative speed of the surfaces. 3. Independent of the area of contact between the surfaces.
Rules for Static Friction (pg. 161)
The force of static friction between two surfaces has the following properties: 1. It takes on any value between zero and the maximum possible force of static friction, ƒs,max = msN 2. It is independent of the area of contact between the surfaces. 0 < ƒs < msN 3. It is parallel to the surface of contact, and in the direction that opposes relative motion.
Latent Heat
The heat that must be added to or removed from one kilogram of a substance to convert it from one phase to another. (During the conversion process, the temperature of the system remains constant.)
Absolute Zero
The lowest temperature below which it is impossible to cool an object.
Amplitude
The maximum extent of a vibration or oscillation, measured from the position of equilibrium. one-half the total range of motion. The maximum magnitude of displacement
Escape Velocity
The minimum velocity that is needed to go into orbit.
Period of a Mass on a Spring
The period of a mass oscillating on an ideal spring is proportional to the square root of the mass, and inversely protional to the square root of the force constant. The period is independent of the ampli- tude of motion.
Special Properties of a Simple Pendulum
The period of simple harmonic motion is independent of amplitude. The fact that the period is also independent of the mass is a special property of the pendulum
Center of Mass
The point where the system can be balanced in a uniform gravitational field.
Destructive Interference
The positive displacement of one wave adds to the negative displacement of the other to create a net displacement of zero. That is, the pulses momentarily cancel one another
Beat frequencies
The rate at which the volume is heard to be oscillating from high to low volume.
Angular Acceleration
The rate of change of angular velocity.
Continuity of Flow
The speed of an incompressible fluid is inversely proportional to the area through which it flows.