AP Physics 2 Ultimate Guide

________ is a positive scalar quantity.

Mass per unit volume of a substance is defined as density.

If a body is fully or partially immersed in a fluid, it experiences an upward force due to the fluid called buoyant force, and the phenomenon is called buoyancy.

It is the volume of fluid that passes through a particular point per unit of time.

f = Av

• f = volumetric flow rate

• A = cross-sectional area

• v = flow velocity v

At comparable heights, the pressure is lower where the flow speed is greater.

The air on the bottom has greater pressure and pushes up on the wing giving the airplane lift force

Pressure is defined as the magnitude of the normal force acting per unit surface area.

P = F/A

• P is pressure

• F is force

• A is the area

Pascal (Pa) 1 Pa = 1 N/m^2 Practical units: atm, bar, torr

It is the pressure due to the liquid.

The density of the fluid is constant.

• A1V1 = A2V2 A1 and A2 (cross-sectional areas)

• V1 and V2 (flow velocities)

• fluid is incompressible.

• fluid’s viscosity is negligible.

• fluid is streamlined.

• the equation is very similar to the conservation of energy with total mechanical energy.

Thermal energy is transmitted from one body to another. Heat is energy in transit.

It is a measure of an object’s internal energy.

• It relates to the macroscopic properties of gases such as pressure, temperature, etc.

• Every gas consists of small particles known as molecules.

• The gas molecules are identical but different from those of another gas.

• The volume of molecules is negligible compared to the volume of gas.

• The density of a gas is constant at all points.

• Consequently, pressure is exerted by gas molecules on the walls of the container.

• No attractive or repulsive force exists between the gas molecules.

Pv = nRT

• P = pressure

• V = volume

• n = no. of moles

• R = Gas constant

• T = temperature

The pressure exerted by N molecules of gas in a container is related to the average kinetic energy.

K avg = 3/2 kb T

• K avg = average kinetic energy

• kb = Boltzmann’s constant

• T = temperature

It gives us a type of average speed that is easy to calculate from the temperature of the gas.

vrms = √3 kb T/ m

• vrms = root mean square velocity

• kb = Boltzmann’s constant

• T = temperature

• m = mass

• The Kinetic theory of gases applies to a large number of particles.

• Some molecules will be moving faster than average and some much slower.

It is a device which uses heat to produce useful work

The movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat

Radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium.

If objects 1 and 2 are in thermal equilibrium with Object 3, then Objects 1 and 2 are in thermal equilibrium with each other.

It is a special case of the law of conservation of energy that describes processes in which only internal energy changes and the only energy transfers are by heat and work.

∆ U = Q + W

• Q = heat added

• W = work done by the system

• ∆ U = change in internal energy

it is used to calculate work done.

Temperature remains constant.

no transfer of heat

pressure remains constant

volume remains constant.

It describes how systems evolve over time.

It is associated with a state of randomness, disorder, or uncertainty.

Heat conducts from one point to another only if there is a temperature difference between the two objects.

In an isolated system, the charge is always conserved.

Protons and electrons have a quality called electric charge.

The charge is invariant in nature.

The charge is quantized.

(Q = n e)e = 1.6 * 10^-19 C

• n = no. of electrons

• Q = charge

It involves addition or removal of electrons.

The electric force between two particles with charges q1 and q2 separated by distance r has a magnitude by the equation:

F = Kq1q2/r^2

• F = force

• K = coulomb’s constant

• q1 and q2 = charges

• r = distance between the charges

The space is surrounded by a charge in which another charged particle experiences the force.

The electric field surrounding the point charge is:

E = 1/4πε0 * Q/r^2

• E = electric field

• Q = charger = distance between charges

• ε0 = permittivity of free space

• Radial field

• It is generated by a collection of point charges.

• An infinite sheet of charge.

The electric fields follow the same addition properties as the electric force.The electric field lines never cross.

A lot of problems deal with the uniform electric field.The field may be taken as uniform at least in the middle.The uniform field just signifies the constant force.

Materials which allow the flow of excess charge without resisting it.

Materials that resist the flow of electrons.

It involves rubbing the insulator against another material, thereby stripping electrons from one to another material.

When we connect two conductors charge flows from one to another until the potential of both the conductors becomes the same.

The process of charging by induction may be used to redistribute charges among a pair of neutrally charged spheres.

There aren’t any free electrons.The atoms make up the sphere will become polarised.

We is the work done by the electric force, then the change in the charge’s electrical potential energy is defined by:

Ue = electrical potential energy

We = work done by electric force

Electrical potential energy required to move along the field lines surrounding a point charge is given by:

• q1 and q2 = charges

• e0 = permeability of free space

• Ue = electrical potential energy

• r = distance

Electric potential is the electric potential energy per unit of charge at a point in an electric field, measured in volts (V). It's the work done per unit charge in bringing a test charge from infinity to that point. V = U/q

Consider the electric field created by a point source charge Q. If a charge moves from a distance rA to a distance rB from Q, then the change in the potential energy is: Ub and Ua = electrical potential energies for a and bra and rb = distances for a and be0 = permeability of free space

An equipotential surface is a surface in a region of space where every point on the surface is at the same potential. In other words, no work is required to move a charge along an equipotential surface. Equipotential surfaces are perpendicular to electric field lines and can be used to visualize the electric field in a given region.

V = kQ/r V = electric potential energyq = point charger = distance between any point around the charge to the point chargek = Coulomb constant; k = 9.0 × 109 N

Equipotential curves are curves of constant elevation. If you walk along any of the contour lines and you neither ascend nor descend, then the curve is known as the equipotential curve.

A drawing of several equipotential curves at various values of the potential for a charge distribution is called an equipotential map.

Two conductors, separated by some distance carry equal but opposite charges +Q and -Q. The pair comprises a system called a capacitor.

The capacitor is in the form of parallel metal plates or sheets.

The capacitance measures the capacity for holding charge.

Fringing fields extend beyond conductor or magnetic material edges. They weaken as the distance from the edge increases. They're important in device design but can cause interference and affect performance.

The energy stored in a capacitor can be calculated using the formula U = 1/2 * C * V^2 where U is the energy stored in joules, C is the capacitance of the capacitor in farads and V is the voltage across the capacitor in volts.

To keep the plates of the capacitor apart they are filled with dielectric which increases the capacitance of the capacitor.

The continuous flow of charge

Iavg = change in charge/ change in time

A battery is a device that maintains an electric potential difference between the two terminals.

The flow is from higher potential to lower potential. The electricity also flows in that direction called direct current.

It is the impedance to the flow of electricity through a material. Asa charge moves through a material, it eventually hits a non-moving nucleus in the material.

It can be thought of as the density of nuclei the electrons may strike. R = ρ l / A R = resistance of the circuitρ = resistivityl = lengthA = cross-sectional area

conductors

insulators

R eq = R1 + R2

1/Req = 1/R1 + 1/R2

An ammeter is a device with a very low resistance that measures the current.

It measures the electric potential called potential drop.

V = IR R is the resistance in the circuit.V is the potential difference in the circuitI is the electric current

P = VIP = I^2 RP = V^2 IRP is the powerV is the potential difference in the circuit.I is the electric current.

The loop rule states that the voltage drop across any complete loop in the circuit is 0V. This statement follows from the conservation of energy when applied to circuits.The junction rule states that the sum of all current flowing into any junction is equal to the current flowing out of the junction. This statement follows from the conservation of charge.

C = QV C = refers to the capacitance that we measure in faradsQ = refers to the equal charge that we measure in coulombsV = refers to the voltage that we measure in volts Besides, there is another formula that appears like this: C = kε0Ad C = refers to the capacitanceK = refers to the relative permittivityε0 = refers to the permittivity of free spaceA = refers to the surface area of the platesd = refers to the distance between places measured

Cp = C1 + C2

1/Cs = 1/C1 + 1/C2

The space surrounding a magnet is called a magnetic field.

We use (x) when the magnetic field goes into the plane.We use (.) when the magnetic field goes out of the plane.

A permanent bar magnet creates a magnetic field that closely resembles the magnetic field produced by a circular loop of current-carrying wire.

F = qv x B with magnitude: F = qv B sin theta F = forceq = chargev = velocityB = magnetic field

Whenever you use the right-hand rule, follow these steps: Orient your hand so that your thumb points in the direction of the velocity v. If the charge is negative, turn your thumb by 180 degrees.Point your fingers in the direction of B.The direction of FB will then be perpendicular to your palm.

F = ILB with magnitude: F = BIL sin theta F = forceB = magnetic fieldI = currentL = length of conductor

B= μo I / 2πr B = magnetic fieldI = applied currentμo = permeability of free spacer = the distance from the wire where the magnetic field is calculated

The induced current will always flow in the direction that opposes the change in magnetic flux that produced it. Emf = -N (ΔΦ/ Δt) ‘Emf’ = Induced voltage or electromotive force.‘N’ = The number of loops.‘Δϕ’ = Change within magnetic flux.‘Δt’ = Change in time

Whenever a conductor is placed in a varying magnetic field, an electromotive force is induced. If the conductor circuit is closed, a current is induced, which is called induced current.The induced emf in a coil is equal to the rate of change of flux linkage. emf = − dΦ/ dtemf = electromotive forcedΦ = change in magnetic fluxdt = change in time

It is created in three ways: Changing the area of the loop of wire in a stationary magnetic field.Changing the magnetic field strength through a stationary circuit.Changing the angle between the magnetic field and the wire loop.

Motional emf is the electromotive force generated by the motion of a conductor through a magnetic field.It is given by the equation emf = Blv, where B is the magnetic field strength, l is the length of the conductor, and v is the velocity of the conductor.This phenomenon is used in various applications, such as electric generators and motors.

Solenoid is a device that is constructed by a series of coaxial wires through which a continuous current flow.

Electromagnetic waves are a type of wave that consists of oscillating electric and magnetic fields that travel through space at the speed of light. They are produced by the acceleration of charged particles and include radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. Electromagnetic waves have a wide range of applications, including communication, medical imaging, and energy production.

It can be categorized by its frequency. The full range of waves is called the electromagnetic spectrum.

The phenomenon of superimposition of two or more waves having the same frequency emitted by two coherent sources.

It is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of the geometrical shadow of the obstacle/aperture.

A diffraction pattern will also form on the screen if the barrier contains only one slit.

The incident light on a barrier that contains two narrow slits, separated by distance d. On the right there is a screen whose distance from barrier L, is much greater than d.

constructive interference: d sinθ = m λ destructive interference: d sinθ = (m+1/2) λ where, m = 0, 1, 2, 3, etc.λ = wavelength of lightd = distance

The angle that the incident beam makes with the normal is called the angle of incidence.

The angle that the reflection makes with the normal is called the angle of reflection.

The angle that the transmitted beam makes with the normal is called the angle of refraction.