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How many jin is a pound, how many two, how many grams, how to convert, which country is the unit
Pounds and ounces are English units, and kilograms and grams are metric units
Conversion: 1 pound = 0.453592 kg (kg) 1 ounces = 28.3495 G
Several problems of quadratic equation of one variable in the third grade of junior high school
1. Solve the following equation about X by formula method: ax square root 2aX + 1 / 2 (A-1 / 2) = 0 (a ≠ 0)
2. (m-5) square x square + 2 (m-5) x + 1 = 0
3. Prove that the value of - 10x square + 7x-4 is always less than 0
4. It is proved that the value of 4x square - 12x + 10 is always greater than 0
5. Solve the equation MX square - (3m + 2) x + 2m + 2 = 0 (M is not 0) with formula method
6. When x is the value, the equation | x square - X-2 | + | 2x square - 3x-2 | = 0 holds
1. The original equation is changed to AX ^ 2 - √ 2aX + 1 / 2a-1 / 4 = 0. Because △ = 2A ^ 2-2a ^ 2 + a = a, and a ≠ 0, when a > 0, x = (√ 2A + √ a) / 2A or x = (√ 2A - √ a) / 2A; when a > 0, x = (√ 2A - √ a) / 2A; when a ≠ 0, x = (√ 2A - √ a) / 2A; when a ≠ 0, x = (√ 2A - √ a) / 2A; when a ≠
A lamp consumes 40 watts of electricity. How much electricity does it consume in one minute and one hour?
twelve thousand three hundred and forty-five
One lamp consumes 40 watts of electricity, one minute of electricity,
40 / 1000 / 60W
Power consumption in one hour
40 / 1000 = 0.04 w
Let a, B and C be integers
Let a, B and C be integers, and prove that if (B - 1) is divisible by a, and (C - 1) is divisible by a, (b * C - 1) can be divisible by A
Certification:
Because B-1 is divisible by A,
So let B-1 = am (where m is an integer)
Similarly, C-1 = an (where n is an integer)
So b * C-1 = (am + 1) (an + 1) - 1
=a^2mn+am+an+1－1
=a(amn+m+n)
So b * C-1 is divisible by A
Jiangsu Wu Yunchao answers for reference!
When other conditions are the same, does the series circuit produce more heat or does the parallel circuit produce more heat?
Parallel multiple
The series circuit needs voltage division, but the parallel circuit does not
Therefore, when other conditions are the same, the voltage at both ends of the consumer in the parallel circuit is greater than that of the consumer in the series circuit
The electric power is sure to be large and the heat is much
If M (3m + 1,4-m) is in the fourth quadrant, then the value range of M is ()
The abscissa of the fourth quadrant is greater than 0
The ordinate is less than 0
3m+1>0
4-m-1/3
m>4
M>4
Calculation of electric power and electrician
For a bulb marked with "6v3w", what is the resistance of the bulb? What is the rated current? If the voltage applied at both ends of the bulb is 110V, what is the actual current passing through it? What is the actual power (assuming that the resistance of the filament remains unchanged)
In accordance with the junior high school problem-solving format
..
Wrong number... In the title "6v3w" should be changed to "pz220 -- 40"
sorry
1, according to P = u ^ 2 * r ------ r = u ^ 2 / P = 1210 Ω
2, according to P = IU -------- I = P / u = 40 / 220 = 0.18a
The resistance does not change
3,I=U/R=110/1210=0.091A
4,P=U^2/R=110*110/1210=10W
A spring with original length L = 10cm, stiffness coefficient k = 1000N / m, and two persons at both ends of the spring pull the spring with 20n horizontal force F
What is the length of the spring at rest within the elastic limit
Here, why use 20n instead of 40n. Why another person's pulling force is invalid
In addition, when the spring is stationary, it will extend 1cm to the left and 1cm to the right, or only 2cm to the left or right, or neither.
According to Newton's third law, suppose that a pulls the spring to the left with a force of 20n. If there is no 20n force that B pulls to the right to balance, then the spring will make a uniform acceleration to the left. The reason is that the resultant force of the spring is constant 20n to the left
However, if a is pulled to the left and B is pulled to the right, the resultant force on the spring is 0, and the spring will be stationary, but it will deform
For example, when a is pulling the spring, the other end of the spring is fixed on the wall, so the spring is still. (but the wall does not seem to exert force on the spring). In fact, when a is pulling the spring, the wall is also pulling the spring to prevent the spring from accelerating to the left, so the wall does not seem to exert force, In fact, the force exerted by the wall on the spring is the same as a, but in the opposite direction
B here is like a wall. The force in the opposite direction is to prevent the spring from moving to the left. Therefore, the tension on the spring is only 20n
As for static, if B is a wall, because the wall will not move, the spring will extend 2cm to the left (assuming a is on the left), but here B is an active force application target, so when the spring is stationary, it will extend 1cm to the left and right respectively. Finally, the balance state is maintained
I hope I can help you
good night
Pure resistance circuit, pure inductance circuit, pure capacitance circuit, the size of the relationship between voltage and current, the gods help
In three kinds of circuits, the greater the voltage, the greater the current. Specifically, see the following calculation methods: 1. The calculation formula of voltage and current in pure resistance circuit: I = u / R; 2. In pure inductance circuit, first use the formula to calculate its inductive reactance: the calculation formula of inductive reactance is: XL = 2 π FL; in the formula, the unit of XL is Ω; F is the electricity through the inductance
The total mass of a trolley and the object on the trolley is m = 1kg. Under the action of constant traction force F = 10N, the trolley starts to move along the horizontal plane from static state,
The resistance of the car is 0.1 times of the weight of the car. It is known that every time the car advances L = 0.1M, it will drop a small object from the car. The mass of the small object dropped each time is 0.01 times of that of the car before it fell. Then, when the acceleration of the car is a = 19m / S ^ 2, how far has the car moved? (g = 10m / S ^ 2, known LG 0.99 = -0.0043, LG2 = 0.0301
Let the object fall x times, a = 19m / S ^ 2, and the mass of the car be m
Ma = f-0.1m * g gives m = 0.5
M = m (1-0.01) ^ x obtains LG M = LG [M (1-0.01) ^ x] > > - 0.0301 = x * (- 0.0043) x = 7
The car moved forward 7 * 0.1 = 0.7m
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