1. average speed Vping = s/t (definition) 2. Useful inference VT2-VO2 = 2as?

3. Intermediate speed vt/2 = Vping = (vt+vo)/2 4. Final speed vt = vo+at?

5. Intermediate position speed VS/2 = [(VO2+VT2)/2] 1/26. Displacement S = V level T = VOT+AT2/2 = VT/2t?

7. Acceleration A =(vt-Vo)/t {With Vo as the positive direction, A and Vo are in the same direction (accelerating) a>0; On the other hand, a < 0}?

8. It is inferred experimentally that δ S = AT2 {δ S is the displacement difference (t) in continuous adjacent equal time}?

Attention:?

(1) The average speed is a vector; ?

(2) When the speed of the object is high, the acceleration is not necessarily high; ?

(3)a=(Vt-Vo)/t is only a measure, not a judgment; ?

2) Free fall?

1. Initial velocity VO = 0 2. Final speed vt = gt?

3. Falling height H = GT2/2 (calculated downward from Vo position) 4. Inference Vt2=2gh?

(3) vertical throwing action?

1. Displacement S = VOT-GT2/22. The final speed vt = VO-gt (g = 9.8m/S2 ≈10m/S2)?

3. Useful inference VT2-VO2 =-2G4. Maximum rising height hm = VO2/2g (from the throwing point)?

5. Round-trip time t = 2vo/g (time for throwing back to the original position)?

1) Flat throwing motion?

1. Horizontal speed: VX = VO 2. Vertical speed: vy = gt?

3. horizontal displacement: x = vot4. Vertical displacement: y = gt2/2?

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

6. Closing speed vt = (vx2+vy2)1/2 = [VO2+(gt) 2]1/2?

The angle between the closing speed direction and the horizontal plane is β: tgβ = vy/VX = gt/v0?

7. Joint displacement: s = (x2+y2) 1/2,?

Angle α between displacement direction and horizontal plane: tgα = y/x = gt/2vo?

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

2) Uniform circular motion?

1. linear velocity v = s/t = 2π r/t 2. Angular velocity ω = φ/t = 2π/t = 2π f?

3. centripetal acceleration a = v2/r = ω 2r = (2π/t) 2R4. Centripetal force fcenter = mv2/r = mω 2r = mr (2π/t) 2 = mω v = f?

5. Period and frequency: t = 1/f 6. Relationship between angular velocity and linear velocity: v = ω r?

7. The relationship between angular velocity and rotational speed ω = 2π n (frequency and rotational speed have the same meaning here)?

3) gravity?

1. Kepler's third law: t2/r3 = k (= 4π 2/gm) {r: orbital radius, t: period, k: constant (independent of the mass of the planet, depending on the mass of the central celestial body)}?

2. Law of gravitation: f = GM1m2/R2 (g = 6.67×10-1n? M2/kg2, the direction is on their connection)?

3. Gravity and gravity acceleration on celestial bodies: GMM/R2 = mg; G = GM/R2 {r: celestial radius (m), m: celestial mass (kg)}?

4. Orbital velocity, angular velocity and period of the satellite: v = (GM/R)1/2; ω=(GM/R3) 1/2； T = 2π (R3/GM) 1/2 {m: mass of central celestial body}?

5. The first (second and third) cosmic velocity V 1 = (G and r)1/2 = (GM/r)1/2 = 7.9 km/s; V2 = 1 1.2km/s； V3= 16.7km/s？

6. Geosynchronous satellite GMM/(r+h) 2 = M4 π 2 (r+h)/T2 {h ≈ 36,000 km, h: height from the earth's surface, r: radius of the earth}?

Attention:?

(1) The centripetal force required for celestial motion is provided by gravity, and the F direction = F million; ?

(2) The mass density of celestial bodies can be estimated by applying the law of universal gravitation. ?

(3) Geosynchronous satellites can only run over the equator, and the running period is the same as the earth's rotation period; ?

(4) When the orbit radius of the satellite decreases, the potential energy decreases, the kinetic energy increases, the speed increases and the period decreases. ?

(5) The maximum circling speed and minimum launching speed of the Earth satellite are 7.9 km/s ...?

1) Ordinary force?

1. gravity g = mg (vertically downward, g = 9.8m/S2 ≈ 10m/S2, acting on the center of gravity, applicable to the vicinity of the earth's surface)?

2. Hooke's law f = kx {direction is along the direction of recovery deformation, k: stiffness coefficient (N/m), x: deformation variable (m)}?

3. Sliding friction force f =μFN {opposite to the relative motion direction of the object, μ: friction coefficient, FN: positive pressure (n)}?

4. Static friction force 0≤f Static ≤fm (contrary to the relative motion trend of objects, fm is the maximum static friction force)?

5. Gravity F = GM1m2/R2 (g = 6.67×10-11n? M2/kg2, the direction is on their connection)?

6. Electrostatic force F = kq1Q2/R2 (k = 9.0×109N? M2/C2, the direction is on their connecting line)?

7. electric field force f = eq (e: field strength N/C, q: electric quantity c, positive charge is subjected to electric field force in the same direction as field strength)?

8. Ampere force f = bilsin θ (θ is the angle between b and l, when L⊥B: f = Bil, when B//L: f = 0)?

9. Lorentz force f = qvbin θ (θ is the angle between B and V, when V⊥B: f = qvb, when V//B: f = 0)?

2) Composition and decomposition of force?

1. The resultant force on the same straight line has the same direction: f = f 1+F2, and the opposite direction: f = f 1-F2 (f 1 > F2)?

2. Synthesis of mutually angled forces:?

When f = (f12+f22+2f1f2cos α)1/2 (cosine theorem) f1⊥ F2: f = (f12+f22)/kloc.

3. resultant force range: | f1-F2 |≤ f≤| f1+F2 |?

4. orthogonal decomposition of force: FX = FCOS β, FY = FSIN β (β is the included angle between the resultant force and the x axis TG β = FY/FX)?

Fourth, dynamics (motion and force)?

1. Newton's first law of motion (law of inertia): an object has inertia, and it always keeps a uniform linear motion state or a static state until an external force forces it to change this state?

2. Newton's second law of motion: f = ma or a = f/ma (determined by external force and consistent with the direction of external force)?

3. Newton's third law of motion: F =-F' {the negative sign indicates that the directions are opposite, and f and f' interact, and the balance force is different from the reaction force. Practical application: recoil motion?

4. The balance f of * * * point force is equal to 0, which summarizes the {orthogonal decomposition method and the intersection principle of three forces}?

5. Overweight: FN>g, weightlessness: fn

6. Applicable conditions of Newton's law of motion: it is suitable for solving low-speed motion problems, for macroscopic objects, for dealing with high-speed problems, and for microscopic particles?

Verb (abbreviation of verb) vibration and wave (mechanical vibration and propagation of mechanical vibration)?

1. Simple harmonic vibration f =-kx {f: restoring force, k: proportional coefficient, x: displacement, and the negative sign means that the direction of f is always opposite to x}?

2. The period of a simple pendulum t = 2π (l/g) 1/2 {l: pendulum length (m), g: local gravity acceleration value, provided that the pendulum angle θ.

3. forced vibration frequency characteristics: f = f driving force?

4. Conditions for occurrence of * * * vibration: F driving force = F solid, A = Max, prevention and application of * * * vibration?

6. Wave velocity v = s/t =λf =λ/t {In the process of wave propagation, one period propagates forward by one wavelength; The wave velocity is determined by the medium itself.

7. Sound wave velocity (in air) 0℃; 332 m/s; 20℃； 344 m/s; 30℃； 349 m/s; (Sound waves are longitudinal waves)?

8. Conditions for obvious diffraction of waves (waves continue to propagate around obstacles or holes): Is the size of obstacles or holes smaller than the wavelength, or is there little difference?

9. Interference conditions of waves: The two waves have the same frequency (the phase difference is constant, the amplitude is similar, and the vibration direction is the same)?

Attention:?

(1) The natural frequency of an object has nothing to do with amplitude and driving force frequency, but depends on the vibration system itself; ?

(2) The wave only propagates vibration, and the medium itself does not migrate with the wave, which is a way to transfer energy; ?

(3) Interference and diffraction are Porter's; ?

1. momentum: p = mv {p: momentum (kg/s), m: mass (kg), v: speed (m/s), and the direction is the same as the speed direction}?

3.Impulse: I = ft {I: Impulse (n？ S), f: constant force (n), t: the action time of force (s), and the direction is determined by f}?

4. momentum theorem: I = Δ p or ft = MVT–MVO {Δ p: momentum change Δ δp = MVT-MVO, which is the vector}?

5. Law of Conservation of Momentum: p = p after the total or p'' can also be m1v1+m2v2 = m1v1'+m2v2'?

6. Elastic collision: δ p = 0; Ek = 0 (that is, the conservation of momentum and kinetic energy of the system)?

7. Inelastic collision δ p = 0; 0 & ltEK & ltδ EKm {δ ek: loss kinetic energy, EKm: maximum loss kinetic energy}?

8. Completely inelastic collision δ p = 0; Δ δek =δekm {connected into a whole after contact}?

9. The object m 1 collides elastically with the stationary object m2 at the initial velocity of v 1.

v 1′=(m 1-m2)v 1/(m 1+m2)v2′= 2m 1v 1/(m 1+m2)？

10. Equal mass elastic collision 9- exchange velocity (kinetic energy conservation, momentum conservation) inference?

1 1. what is the mechanical energy loss when the horizontal velocity vo of the bullet m shoots at the long wooden block m resting on the horizontal smooth ground and is embedded in it to move together?

E loss = mvo2/2-(m+m) vt2/2 = fs relative to {vt: * * same speed, f: resistance, s relative to the displacement of the bullet relative to the long block}?

1. work: w = fscos α (definition) {w: work (j), f: constant force (n), s: displacement (m), α: angle between f and s}?

2. Work done by gravity: WAB = mghab {m: mass of object, g = 9.8m/S2 ≈ 10m/S2, hab: height difference between A and B (hab = ha-HB)}?

3. Work done by electric field force: wab = quab {q: electric quantity (c), uab: potential difference (v) between A and B, that is, uab = φ a-φ b}?

4. Electric work: w = UIT (universal) {u: voltage (v), I: current (a), t: power-on time (s)}?

5. power: p = w/t (definition) {p: power [w], w: work done in time (j), t: time taken to do work (s)}?

6. Automobile traction power: p = FvP class = Fv class {P: instantaneous power, p: average power}?

7. The car starts with constant power and constant acceleration, and the maximum running speed of the car (VMAX = P /f)?

8. electric power: p = ui (universal) {u: circuit voltage (v), I: circuit current (a)}?

9. Joule's Law: q = i2rt {q: electrothermal (j), i: current intensity (a), r: resistance value (ω), t: electrifying time (s)}?

10. I = u/r in pure resistance circuit; p = UI = U2/R = I2R； Q=W=UIt=U2t/R=I2Rt？

1 1. kinetic energy: ek = mv2/2 {ek: kinetic energy (j), m: m/s)} object (kg), v: instantaneous velocity of object (m/s)}?

12. gravitational potential energy: EP = mgh {EP: gravitational potential energy (j), g: gravitational acceleration, h: vertical height (m) (from zero potential energy surface)}?

13. potential: ea = qφA {ea:A point charged body potential (j), q: electric quantity (c), φA:A point potential (v)}?

14. kinetic energy theorem (positive work is done on an object, and the kinetic energy of the object increases):?

W = mvt2/2-mvo2/2 or w = Δ ek?

{W = total work done by external force on an object, δEK: kinetic energy change δEK =(mv T2/2-MVO2/2)}?

15. conservation law of mechanical energy: Δ δe = 0 or ek 1+ep 1 = ek2+ep2 can also be mv12+mgh1= mv22/2+mgh2?

16. Variation of gravitational work and gravitational potential energy (gravitational work equals negative value of gravitational potential energy increment of an object) WG =-δ EP?

Attention:?

(1) power indicates how fast work is done, and how much work is done indicates how much energy is converted; ?

(2)O0≤α& lt； 90O do positive work; 90O & ltα≤ 180O does negative work; α = 90o does no work (when the direction of force is perpendicular to the direction of displacement (velocity), the force does no work); ?

(3) If gravity (elasticity, electric field force and molecular force) does positive work, the potential energy of gravity (elasticity, electricity and molecule) will decrease?

(4) Gravity work and electric field force work are independent of the path (see Equations 2 and 3); (5) Condition of conservation of mechanical energy: Except gravity (elasticity), other forces do not do work, but only convert between kinetic energy and potential energy; (6) Conversion of energy in other units: 1kWh (degree) = =3.6× 106J,1ev =1.60×10-19j; *(7) Spring elastic potential energy E = kX2/2, which is related to stiffness coefficient and deformation. ?

Eight, molecular dynamics theory, the law of conservation of energy?

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

2. Measurement of molecular diameter by oil film method d=V/s {V/s {v: single molecule oil film volume (m3), s: oil film surface area (m) 2}?

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. Intermolecular attraction and repulsion (1) r

(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, f molecular force shows 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, two ways to change the internal energy of an object, the effect is equivalent),?

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?

7. The third law of thermodynamics: thermodynamic zero cannot be reached (lower limit temperature of the universe: -273. 15 degrees Celsius (thermodynamic zero))?

Attention:?

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

(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; ?

X. electric field

1. Two kinds of charges, law of charge conservation and elementary charge: (e =1.60×10-19c); Is the charge of a charged body equal to an integer multiple of the elementary charge?

2. Coulomb's law: f = kq 1q2/r2 (in vacuum) {f: the force between point charges (n), k: the electrostatic constant k = 9.0× 109N? M2/C2, Q 1, Q2: the electric quantity of two charges (c), R: the distance between two charges (m), and the direction is on their connecting line. Action and reaction, such as charges repel each other and different charges attract each other.

3. Electric field intensity: e = f/q (definition formula, calculation formula) {e: electric field intensity (N/C), which is a vector (electric field superposition principle), q: electric quantity for checking charge (c)}?

4. The electric field formed by the vacuum point (source) charge e = kq/R2 {r: the distance from the source charge to this position (m), q: the electric quantity of the source charge}?

5. The field strength of uniform electric field E = UAB/D {the voltage between two points UAB: AB (V), and the distance between two points D: AB (M) in the field strength direction}?

6. electric field force: f = QE {f: electric field force (n/c)}, q: electric charge (c) affected by electric field force, e: electric field intensity (N/C)}?

7. Potential and potential difference: UAB = Φ a-Φ b, UAB = wab/q =-Δ eab/q?

8. Work done by electric field force: WAB = Kwab = EQD {WAB: Work done by electric field force when charged body goes from A to B (J), Q: Charged amount (C), UAB: potential difference (V) between points A and B in electric field (the work done by electric field force has nothing to do with the path), E: uniform electric field strength, and D: along the field strength direction.

9. Electric potential energy: ea = q φ a {ea: electric potential energy of charged body at point A (J), q: electric quantity (C), φ a: electric potential at point A (V)}?

10. change of electric potential energy δEAB = e B-EA {difference of electric potential energy when charged body moves from position a to position b in electric field}?

1 1. Work done by electric field force and change of electric potential energy δ eab =-wab =-quab (the increment of electric potential energy is equal to the negative value of work done by electric field force)?

12. capacitance c = q/u (definition formula, calculation formula) {c: capacitance (f), q: electric quantity (c), u: voltage (potential difference between two plates) (v)}?

13. Capacitance of parallel plate capacitor c = ε s/4 π KD (S: area of two plates facing each other, D: vertical distance between two plates, ω: dielectric constant)?

14. acceleration of charged particles in electric field (VO = 0):w =δek Δ ek or qu = mvt2/2, vt = (2qu/m) 1/2?

15. Deflection of charged particles when they enter a uniform electric field at the speed Vo along the vertical electric field direction (regardless of gravity)?

Quasi-flat vertical electric field direction: uniform linear motion L = VOT (in parallel plates with E=U/d heterogeneous charges: E = U/D)?

Throwing motion is parallel to the direction of electric field: uniformly accelerated linear motion with zero initial velocity D = AT2/2, A = F/M = QE/m?

Attention:?

(1) When two identical charged metal balls are in contact, the power distribution law is that different kinds of original charges are neutralized first and then evenly divided, and the total amount of the same kind of original charges is evenly divided; ?

(2) The electric field line starts with positive charge and ends with negative charge. The electric field lines do not intersect, and the tangent direction is the field strength direction. The electric field is strong where the electric field lines are dense, and the potential along the electric field lines is getting lower and lower, and the electric field lines are perpendicular to the equipotential lines; ?

(3) memorize the electric field line distribution requirements of common electric fields (see Figure [Volume II P98]); ?

(4) The electric field strength (vector) and electric potential (scalar) are determined by the electric field itself, and the electric field force and electric potential are also related to the electric quantity and the positive and negative charges of the charged body; ?

(5) In electrostatic balance, the conductor is an equipotential body with an equipotential surface, the electric field line near the outer surface of the conductor is perpendicular to the surface of the conductor, the synthetic field strength inside the conductor is zero, there is no net charge inside the conductor, and the net charge is only distributed on the outer surface of the conductor; ?

(6) Capacitance unit conversion:1f =106μ f =1012pf; ?

(7) Electron Volt (eV) is the unit of energy,1EV =1.60×10-19j; ?

XI。 Constant current?

1. current intensity: i = q/t {i: current intensity (a), q: the amount of electricity passing through the lateral load surface of the conductor in time t (c), t: time (s)}?

2. Ohm's Law: I = u/r {i: conductor current intensity (a), u: voltage across the conductor (v), r: conductor resistance (ω)}?

3. Resistance, resistance law: r = ρ l/s {ρ: resistivity (ω? M), l: conductor length (m), s: conductor cross-sectional area (m2)?

4. Ohm's Law of Closed Circuit: I = E/(R+R) or E = IR+IR, or E = U inside +U outside?

{I: total current in the circuit (A), E: electromotive force of power supply (V), R: external circuit resistance (ω), R: internal resistance of power supply (ω)}?

5. Electric power and power: w = UIT, p = UI {w: electric power (j), u: voltage (v), I: current (a), t: time (s), p: electric power (w)}?

6. Joule's Law: q = i2rt {q: electrothermal (j), i: current passing through conductor (a), r: resistance value of conductor (ω), t: electrifying time (s)}?

7. In a pure resistance circuit: Because I = u/r, W = q, W = q = UIT = I2RT = U2T/r?

8. Total power activity, power output and power efficiency: pTotal = IE, pOutput = IU, η = ptout/ptotal {i: total circuit current (a), e: power electromotive force (v), u: terminal voltage (v), η: power efficiency}?

9. Series/parallel series circuit of the circuit (P, U is proportional to R) Parallel circuit (P, I is inversely proportional to R)?

Resistance relation (series, same and opposite) R series = r1+R2+R3+1/rparallel =1/r1+kloc-0//R3+?

The current relation I is always = I1= I2 = i3 and = i 1+I2+i3+?

The voltage relationship utotal = u1+U2+u3+utotal = u1= U2 = u3?

Power distribution Ptotal = p1+P2+P3+Ptotal = p1+P2+P3+?