The solution process is as follows:

The commonly used physical formulas are as follows:

I. Electric Power Formula

(1) p = w/t = ui (general formula)

(2) p = i2r = U2/r (pure resistance formula)

Second, the electric power formula

(1) w = UIT = PT = UQ (general formula)

(2) W = I ∧ 2RT = U ∧ 2t/r (pure resistance formula)

Third, the current formula.

1, current intensity: I = Q power /t

2. Resistance: R=ρL/S

3. ohm's law: I = u/r

4, Joule's law:

(1) Q = I2RT general formula)

(2) Q = UIT = Pt = UQ = U2t/r (pure resistance formula)

Fourth, the circuit formula

1, series circuit:

( 1)I=I 1=I2

(2)U=U 1+U2

(3)R=R 1+R2

(4) U 1/U2 = R 1/R2 (partial pressure formula)

(5)P 1/P2=R 1/R2

2. Parallel circuit

( 1)I=I 1+I2

(2)U=U 1=U2

(3) 1/R = 1/R 1+ 1/R2[R = R 1r 2/(R 1+R2)]

(4) i 1/I2 = R2/r 1 (shunt formula)

(5)P 1/P2=R2/R 1

Verb (abbreviation of verb) thermal formula

1, endothermic: q endothermic = cm (t-t0) = cm δ t.

2. heat release: q = cm (t0-t) = cm δ t.

3. calorific value: q = q/m

4. Efficiency of furnace and heat engine: η = q effective utilization rate /Q fuel.

5. thermal balance equation: q- discharge = q- suction.

6. Thermodynamic temperature: t = t+273 K.

7. Fuel combustion exothermic formula Q absorption = MQ or Q absorption = VQ (applicable to natural gas, etc. )

8, mechanical efficiency

η = w you /W total = p you /P total

(η = g/FH in pulley block)

(1) η = g/HF (vertical direction)

(2) η = g/(g+g motion) (excluding vertical friction)

③η= f/HF (horizontal direction)

Six, the formula of work

W = fs w = GH When you lift an object very high? W=Pt

Seven. Velocity formula

Basic formula: v=s/t

Distance traveled by the train when crossing the bridge (hole) S = L bridge +L train.

The speed of sound in the air is 340 meters per second.

The propagation speed of light in air is 3× 108 m/s.

Eight. density

ρ=m/v

formula

(ρ water =1.0×10.3 kg/m3)

Nine, work and power formula

W=FS=GH

P=W/t