The accumulated contents of the Vocabulary Manual of the fourth grade Chinese lesson 30 in compulsory education nothing 2003 compulsory education curriculum standard experimental textbook Chinese grade 4 Volume 1 Vocabulary Manual lesson 30

The accumulated contents of the Vocabulary Manual of the fourth grade Chinese lesson 30 in compulsory education nothing 2003 compulsory education curriculum standard experimental textbook Chinese grade 4 Volume 1 Vocabulary Manual lesson 30

1、 Zhan Tianyou is an outstanding patriotic Engineer in our country. Second, the Qing government appointed Zhan Tianyou as the chief engineer in charge of the construction of the Beijing Zhangjiakou Railway when the imperialist countries were fighting for the right to build the railway. Third, foreigners thought that there were no Chinese who could build the Beijing Zhangjiakou Railway

People's education press Chinese fifth grade volume I Vocabulary Manual accumulated over time

Fifth grade primary school Volume I words inventory and accumulated words inventory 1 (reading, writing) signs anxious, afraid of interest patronage, I'm afraid there are enough reasons. Eaves actually support, encourage around entertainment, sigh, travel, think, taste fragments, ignore the meaning way, torrential rain without hesitation (reading, writing) greed

A new building has been built in a unit. The water pipes are laid from the main water pipe 132 meters away. There are two kinds of water pipes 8 meters long and 5 meters long for selection. (1) please design a scheme. How to select these two kinds of water pipes so that they can be laid from the main pipe to the building? How many plans are there? (2) If each 8-meter-long water pipe costs 50 yuan, and each 5-meter-long water pipe costs 35 yuan, which one is the most economical?

(1) According to the meaning of the title, we can get: 8x + 5Y = 132, the solution is: x = 4Y = 20, x = 9y = 10, x = 14y = 4, so there are three schemes; (2) ① 50 × 4 + 20 × 35 = 900 (yuan); (2) 50 × 9 + 10 × 35 = 800 (yuan); (3) 50 × 14 + 4 × 35 = 840 (yuan)

What else can electricity be converted into

Electric energy can be converted into almost any form of energy! Such as mechanical energy: motor, chemical energy: battery, heat energy: electric heater, light energy: electric lamp, wind energy: electric fan, water energy: water pump

How to factorize 2 (A-3) & # - A + 3?

The original formula = 2 (A-3) ² - (A-3)
=(a-3)[2(a-3)-1]
=(a-3)(2a-7)

How many grams is a cow?

G=mg g=9.8kg/N m=1N/9.8Kg/N
m=0.102041Kg
m=102.04g

Find out the number of (2 + 1) (the 2nd power of 2 + 1) (the 4th power of 2 + 1) ·· (the 32nd power of 2 + 1)

(2+1)(2^2+1)(2^4+1)…… (2^32+1)
=(2-1)(2+1)(2^2+1)(2^4+1)…… (2^32+1)
=(2^2-1)(2^2+1).(2^32+1)
=...
=(2^32-1)(2^32+1)
=2^64-1
2 ^ n bits are in cycles of 2, 4, 8, 6
64÷4=16
One bit is 6-1 = 5

Two electric lamps L1 and L2 are connected in series in the 220 V circuit. It is known that their resistances R1 and R2 are 440 V and 110 V respectively!

The current in series is equal everywhere. Maybe it has nothing to do with the proportional method
Solution: R total = R1 + R2 = 440V + 110V = 550V
I=U/R=220V/550V=0.4A
(the total resistance in series is equal to the sum of each resistance, so there is R1 + R2)
I wish you the best in physics

The projection of one vector in the direction of another
Let θ be the angle between a and B, then___________ It's called the projection of a in the direction of B____________ It is called the projection of B in the direction of A. the projection of B in the direction of a is a number, not a vector. When 0 degree is equal to 90 degree, it is___________ When 90 degrees θ = 180 degrees, it is________ When θ = 90 degrees, it is_____________ .

This is the key to use the value of cos θ to calculate
In addition, notice the value range of cos θ
The five empty answers are
acosθ
bcosθ
Positive number
negative
0

Junior high school physics electric power formula

Current definition formula: I = q / T
In series circuit:
(1) I total = I1 = I2 = i3
(2) U total = U1 + U2 + u3
(3) R total = R1 + R2 + R3
In parallel circuit:
(1) I total = I1 + I2 + i3
(2) U total = U1 = U2 = u3
(3) 1 / R total = 1 / R1 + 1 / r2 + 1 / R3
Ohm's Law: u = IR
Electric power formula:
P=W/t
P=UI
P=I²R
P=U²/R
Electric work formula:
W=Pt
W=UIt
W=I²Rt
W=U²t/R
W = UQ (in this formula, q is the amount of charge, and Q is in Coulomb)
Joule's Law: q = I & sup2; RT
The total function of the current is calculated by the formula w = uit
The heat generated by current is calculated by Joule's law, q = I & sup2; RT
(if calculating how much mechanical energy is converted from electrical energy: uit-i & sup2; RT)
When all the work done by the current is converted into heat Q, w = Q
No matter series parallel circuit:
Wtotal = W1 + W2 + W3
Ptotal = P1 + P2 + P3
Qtotal = Q1 + Q2 + Q3
When calculating the actual power of electrical appliances: P real = (U real / u amount) & sup2; P amount