Electric power calculation Q: if a light bulb is marked with "220V 40W", how much power will it consume when it works normally for 10 minutes? (Note: it is required to state clearly the calculation basis of each step.) We use kw.h/j as the unit to work out a solution respectively, and then make the two results mutually.

Electric power calculation Q: if a light bulb is marked with "220V 40W", how much power will it consume when it works normally for 10 minutes? (Note: it is required to state clearly the calculation basis of each step.) We use kw.h/j as the unit to work out a solution respectively, and then make the two results mutually.

This "220V 40W" means that the power consumption is 40W * 3600s = 144000j when working normally for one hour under the voltage of 220V. Now working for 10 minutes is 1g6h, and the power consumption is 40W * 600s = 24000j. For the calculation of kW. H, you can directly use 0.04kw * 1 / 6H = 0.0067kw. H, or you can use 24000j, and the base is 1kW. H = 3600000j

On electric power calculation
Why can the formula w = IUT be used to calculate the electric work of any circuit, but the two variants of Ohm's law can only be used for pure resistance circuits?

Because pure resistance circuit has Ohm's law, u = IR
Then it can be transformed into w = I ^ 2rt or w = u ^ 2 / RT

When two sinusoidal quantities with the same frequency are added, why is the phase difference the largest when it is zero

Because when the phase difference is 0, it is equal to direct addition; when it is 180, it is opposite, it is equal to subtraction; when it is 90 °, it is equal to positive limit

Mathematical problems of bicycle tires
If a bicycle tire is installed on the front wheel, it will be scrapped after 5000 km; if it is installed on the rear wheel, it will be scrapped after 3000 km, and the front and rear tires can be exchanged after a certain distance. If the front and rear tires are exchanged, how many km will a bicycle run if a pair of new tires are scrapped at the same time

Suppose the total wear of each new tire is k, then the wear of the tire installed on the front wheel is k | 5000 per kilometer, and the wear of the tire installed on the rear wheel is k | 3000 per kilometer

The equation for a circle with the center of the circle on y = - X and passing through two points a (2,0), B (0,4)

I am a sophomore in the Department of mathematics of Northeast University. Let the equation of a circle be (x-a) ^ 2 + (y + a) ^ 2 = R ^ 2, and then substitute the coordinates of a and B to get two equations, and then solve the equation
The center of the circle must be on the AB vertical bisector. First, find out the AB vertical bisector equation L, and then find out the intersection of L and y = - x, which is the center of the circle. If the center of the circle is found out, the radius is naturally easy to get

The transport team transported a batch of rice to the disaster area. In the morning, it took 4 trucks to transport 25, with an average of 20% per truck______ What about the rest of the rice______ The car can't be finished

How many parts of this batch of rice can be transported by each truck on average: 25 △ 4, = 25 × 14, = 110; how many trucks can the rest of the rice be transported by: (1-25) △ 110, = 35 △ 110, = 6 (trucks); a: 110 of this batch of rice can be transported by each truck on average, and the rest of the rice can be transported by 6 trucks

If the solution of the equation 3x + 2A = 1 and the solution of the equation x-2a = 0 are opposite numbers, find a

Because the solutions of the two equations are opposite to each other, the solution of the former equation is
-2A. Substituting - 2A into the first equation, we can get the equation about A. then we can solve it

The perimeter of the bottom surface of a pile of conical yellow sand is 25.12 meters, and the height is 1.5 meters. If the weight of yellow sand is 1.5 tons per cubic meter, how many tons of yellow sand are there in total

First, calculate the radius of the cone bottom: 25.12/3.14/2 = 4m
Cone area: 3.14 × 16 × 1.5 / 3 = 25.12 square meters
25.12 times 1.5, total tonnage

Given the line L: y = 2x-1, (1) find the analytic formula of the line L2 which is symmetric about X axis, (2) the area of the triangle formed by two lines and Y axis

① On the x-axis and y-axis symmetry, the slope of the straight line is opposite and the intercept is opposite
∴L2：y=-2x+1
② Let X1 = 0 get Y1 = - 1, let x2 = 0 get y2 = 1, and the intersection of two lines is (1 / 2,0)
∴S=1/2*|1-(-1|*1/2=1/2

There are 56 students in class 61. There are 25% more boys than girls. How many girls are there

25% less
56 (1 + 75%) = 32