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Explain 3B's Square = 9b's Square with geometric figure
Draw a square with a side length of 3b, and then divide it into nine small squares with a side length of B,
Area: (3b) ^ 2 = 9b ^ 2
When an aircraft flies between two cities, the wind speed is 24 km / h, it takes 2 hours and 50 minutes to fly along the wind and 3 hours to fly against the wind. (1) calculate the flight speed when there is no wind; (2) calculate the distance between two cities
(1) Let the speed of the aircraft be x km / h when there is no wind, and the distance between the two cities be s km. Then the speed V1 = x + 24 when flying along the wind, V2 = x-24 when flying against the wind, s = v1t1 when flying along the wind, s = v2t2 when flying against the wind, that is, s = (x + 24) × 256 = (x-24) × 3, and the solution is x = 840. A: the speed of the aircraft is 840 km / h when there is no wind- 24) × 3 = 2448 km a: the distance between the two cities is 2448 km
Make two cuboid cartons with the following dimensions (unit: cm): length width height small carton a B C large carton 2A 2B 1.5C (1) calculate the volume V1 of the large carton and the volume V2 of the small carton; (2) how many square centimeters of cardboard do these two cartons share?
(1) According to the title: V1 = 2A × 2B × 1.5C = 6abc (cm3), V2 = ABC (cm3); (2) ∵ the surface area of small carton is (2Ab + 2Ac + 2BC) cm2, the surface area of large carton is & nbsp; (8ab + 6ac + 6BC) cm2, ∵ make the two cartons share cardboard (2Ab + 2Ac + 2BC) + (8ab + 6ac + 6BC) ∵
Wang Ping's home is s km away from the school. If he rides a bicycle from home to school in the morning at a speed of V1 km / h and returns home in the afternoon at a speed of V2 km / h (V1 is not equal to V2), is the average speed of his two cars v1 + V2 km / h
It's not the average speed v = s / T, so it should be the total distance divided by the total time
T1 = s / V1 T2 = s / V2 total time is T1 + T2 total distance is 2S
So the average velocity = 2S / (T1 + T2) = 2 * V1 * V2 / (V1 + V2)
The rated power of an electric fan is 60W, and the resistance is 2 ohm. When it operates normally under the voltage of 220V, how much current is passing through it,
How much electric energy is converted into mechanical energy per second? If the electric fan can't rotate for some reason after the power is connected, what is the current intensity through it? What is the actual power consumed by the electric fan?
Rated power refers to the output power?
(1）I=60W/220V=0.273A
(2) Pmechanical = ptotal-pthermal = 60w-i square * 2 ohm = 59.85w
W=PT=59.85J
(3) I = 220 V / 2 ohm = 110 A
(4) P = 110A square * 2ohm = 24200w
The focus of the ellipse X212 + Y23 = 1 is F1, and the point P is on the ellipse. If the midpoint m of the line segment Pf1 is on the Y axis, then the ordinate of the point m is ()
A. ±34B. ±32C. ±22D. ±34
Let the coordinate of point p be (m, n). According to the meaning of the title, we can know that the F1 coordinate is (3, 0) ∧ m + 3 = 0 ∧ M = - 3. Substituting it into the elliptic equation, we can get the ordinate of n = ± 32 ∧ m is ± 34, so we choose a
All power sources convert chemical energy into electrical energy. What's wrong
Power charging and discharging are different
Charging: changing electric energy into chemical energy
Discharge: chemical energy to electric energy
Online, etc. (100 points,
Einstein said that any object can't exceed the speed of light. If it exceeds the speed of light, time will flow backwards. In fact, there are things that exceed the speed of light in the world, but they can't carry actual information. Then I want you to do a small experiment to prove that you can catch up with you in the past and see you in the past
After reaching the speed of light, you can catch up with the previous light and see the past
If the actual power of an electrical appliance is p = 200W and the resistance is r = 220, what is the difference between the actual voltage U and the rated voltage?
p=U²/R=p=U²/220=200,U²=44000
Rated UE = 220, UE - √ U & # 178; = 10.24 V
The difference between actual voltage U and rated voltage is 10.24 v
In the arithmetic sequence {an}, a & #; = 1 / 3, the sum of the first n terms is Sn, if S &;, 2S &;, 3S &; are proportional sequence, then log3an=
If an > 0, then the tolerance of the arithmetic sequence is d (d > 0), then from the summation formula Sn = Na1 + n (n-1) / 2 * D and the known a &; = 1 / 3, we can get: S &; = A &; = 1 / 3, S &; = 2 / 3 + D, namely: 2S &; = 4 / 3 + 2ds &; = 1 + 3D, namely: 3S &; = 3 + 9D, if S &
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