Physics senior two formula

The physics senior two formula is summarized as follows:

Summary of physical formulas 1:

1. Magnetic induction intensity is a physical quantity used to express the strength and direction of magnetic field, and it is a vector in t).

2. Ampere force F = BIL；; (note: L⊥B){B: magnetic induction intensity (t), f: ampere force (f), I: current intensity (a), l: wire length (m)}.

3. Lorentz force f=qVB (note v ⊥ b); M/s)} Spectrometer {f: Lorentz force (n), q: charged particle charge (c), v: charged particle velocity (m/s)}.

4. In the case of ignoring gravity (regardless of gravity), the movement of charged particles into the magnetic field (master two kinds):

(1) charged particles enter the magnetic field along the direction of parallel magnetic field: do uniform linear motion without Lorentz force, V=V0.

(2) Charged particles enter the magnetic field along the direction perpendicular to the magnetic field: make uniform circular motion, and the law is as follows: a)F direction = FLUO = MV2/R = mω 2r = Mr (2π/t) 2 = qvb; r = mV/qB； t = 2πm/qB； (b) The period of motion has nothing to do with the radius and linear velocity of circular motion, and Lorentz force does no work on charged particles (anyway);

The key to solving the problem: draw the trajectory, find the center of the circle, and determine the angle between the radius and the center of the circle (= twice the tangent angle).

note:

The directions of (1) Ampere force and Lorentz force can be determined by the left-hand rule, but Lorentz force should pay attention to the positive and negative of charged particles.

(2) We should master the characteristics of magnetic induction lines and the distribution of common magnetic fields;

(3) Other related contents: principle of geomagnetic field/magnetometer/cyclotron/magnetic materials.

Physical formula abstract 2:

Flat throwing motion:

1. Horizontal speed: Vx=V0.

2. Vertical speed: Vy=gt.

3. Horizontal displacement: x=V0t.

4. Vertical displacement: y=gt2/2.

5. Exercise time t=(2y/g) 1/2 (usually expressed as (2h/g) 1/2).

6. The closing speed vt = (vx2+vy2)1/2 = [v02+(gt) 2]1/2, and the angle between the closing speed direction and the horizontal plane is β:tgβ=Vy/Vx=gt/V0.

7. Combined displacement: s=(x2+y2) 1/2, and the included angle between the displacement direction and the horizontal plane is α:tgα=y/x=gt/2Vo.

8. Horizontal acceleration: ax = 0；; Vertical acceleration: ay = g.

Emphasize:

(1) Flat throwing motion is a curvilinear motion with uniform change, and the acceleration is g, which can usually be regarded as the synthesis of uniform linear motion in horizontal direction and free falling motion in vertical direction;

(2) The movement time is determined by the falling height h(y) and has nothing to do with the horizontal throwing speed;

(3) The relationship between θ and β is TGβ= 2tgα；;

(4) The time t of flat throwing is the key to solving the problem;

(5) An object moving along a curve must have acceleration. When the direction of velocity and the direction of resultant force (acceleration) are not in a straight line, the object moves in a curve.

Physical formula summary 3:

Formula of law of conservation of energy:

1.Avon gadro constant na = 6.02×1023/mol; The molecular diameter is about 10- 10m.

2. The molecular diameter measured by oil film method is d=V/s{V: the volume of monomolecular oil film (m3), and s: the surface area of oil film (m2)}.

3. Content of molecular dynamics theory: Matter is composed of a large number of molecules; A large number of molecules do random thermal motion; There are interactions between molecules.

4. The intermolecular attraction and repulsion:

( 1)r & lt； ; R0, f reference

(2)r=r0, f citation =f repulsion, f molecular force =0, and e molecular potential energy =Emin (minimum value).

(3)r & gt； ; R0，f quote >； ; F repulsion and f molecular force represent gravity.

(4)r & gt； ; 10r0, f =f repulsion ≈0, f molecular force ≈0, e molecular potential energy ≈0.

5. The first law of thermodynamics: w+q = Δ u {(work and heat transfer, the two ways to change the internal energy of an object are equivalent in effect), w: positive work done by the outside world on the object (j), q: heat absorbed by the object (j), Δ u: increased internal energy (j), which involves that the perpetual motion machine of the first kind cannot be built.

6. The second law of thermodynamics:

Kirkhner's statement: it is impossible to transfer heat from a low-temperature object to a high-temperature object without causing other changes (directionality of heat conduction);

Kelvin's statement: it is impossible to absorb heat from a single heat source and use it all to do work without causing other changes (directionality of mechanical energy and internal energy transformation) {it involves that the second type of perpetual motion machine cannot be built.

7. The third law of thermodynamics: thermodynamic zero is unattainable (lower limit temperature of the universe: -273. 15 degrees Celsius (thermodynamic zero)).

note:

(1) Brownian particles are not molecules. The smaller the Brownian particle, the more obvious Brownian motion, and the higher the temperature, the more intense Brownian motion.

(2) Temperature is a sign of average kinetic energy of molecules;

(3) Intermolecular attraction and repulsion exist at the same time, and decrease with the increase of intermolecular distance, but the repulsion decreases faster than attraction;

(4) When the molecular force does positive work, the molecular potential energy decreases, and at r0, F attraction =F repulsion, and the molecular potential energy is the smallest;

(5) The gas expands, and the outside world does negative work on the gas W; 0; Absorb heat, Q>；; 0。

(6) The internal energy of an object refers to the sum of all kinetic energy of molecules and molecular potential energy of an object. For an ideal gas, the intermolecular force is zero and the molecular potential energy is zero;

(7)r0 is the distance between molecules at molecular equilibrium; Content: Geomagnetic field/Magnetometer Principle/Cyclotron/Magnetic Materials.