31 questions for analysis. Thank you! Solve 23 questions! Thank you!

From the geometric relationship, it can be seen that AD=2L, the external circuit is equivalent to a 3R and 2R parallel circuit.

The total resistance of the external circuit is R, and the internal resistance of the power supply is R

The voltage distributed by the terminal voltage is: u=

The current through the ABCD line is: I1 = 6E 11 * 3R = 2E 11r The current through the AD line is: I2 = 6E 11 * 2R = 3E 11R The current is found, and then the ampere force is found in sections.

BC segment: FBC=BI1L=2Bel 11R, the direction is vertically upward.

AB segment: FAB = BI1L = 2Bel 11R, the direction is perpendicular to AB and oblique upward.

CD segment: FCD = Bi1L = 2Bel 11R, the direction is perpendicular to CD and oblique upward.

AD segment: fad=bi2l=3bel 11r, the direction is vertically upward.

The components of FAB and FCD are balanced in the horizontal direction and superimposed in the vertical direction, and the resultant force is FABCD=2Bel 11R

The answer is C

The effective force length is 2 l and the current is e r, which can be solved according to the force formula of the charged conductor in the magnetic field.

H2SO4 is understood as 2 H+ and 1 SO42-, and H2O is understood as 2 H and 1O

Mass of h = 100x10% = 10g

Let so42- be xg, then o be (90-x)g.

1 SO4 and 1 O both correspond to 2H, so.

x/96+（90-x）/16=10/2

x=12, so the mass of SO42- is 12g

So the mass of H2SO4 is.

So the mass of cuo is 10g

So the mass fraction is 50%.

a(n+2)-a(n+1)=2a(n+1)-2an=2[a(n+1)-an]

a(n+2)-a(n+1)] [a(n+1)-an]=2, which is the fixed value a2-a1=4-1=3

A number series is a proportional series with 3 as the first term and 2 as the common ratio.

a(n+1)-an=3·2ⁿ⁻¹=3·2ⁿ-3·2ⁿ⁻¹a(n+1)-3·2ⁿ=an-3·2ⁿ⁻¹a1-3·2⁰=1-3=-2

A sequence is a constant sequence of numbers with terms of -2.

an-3·2ⁿ⁻¹=-2

an=3·2ⁿ⁻¹2

When n=1, a1=3·2 -2=1;When n=2, a2=3·2 -2=4 satisfies the expression.

The general formula for the series is an=3·2 2

The equation gives x=70+4y

Substitut equation 3(70+4y)-2y=50

y=-16x=6