How many square meters is 4.5 mu The width is 43.2 meters. How many meters is the length

How many square meters is 4.5 mu The width is 43.2 meters. How many meters is the length

1 mu 666 M2 2 / 3
4.5 * 666 M2 2 / 3 = 3000 m2
When the width is 43.2m and the length is 3000 / 43.2 = 69.4m

The square of (- 2A + 2b) is equal to
Such as the title

(-2a+2b)²=（-2a）²-2×（-2a）×（2b）+（2b）²=4a²-8ab+4b²

(a-b) square - 2A + 2B + 1 = 0, then what is A-B equal to?

(a-b) square - 2A + 2B + 1 = 0
(a-b)^2-2(a-b)+1=0
(a-b-1)^2=0
a-b=1

How many mu of a piece of land should be measured

First measure the length and width, which is the most basic. Get two numbers and then multiply them. The square meter. 666.667 square meter is equal to one mu, so just divide the square meter by 666.667, which is the mu. For example: 30 meters wide, 30 meters long. 30 * 30 = 900 square meters, 900 divided by 666.667 = 1.34 mu

When a metal block is weighed in air, the indication of the spring scale is 54 n; when it is immersed in water, the indication of the spring scale is 34 n. (g = 10 N / kg)
Ask for:
How buoyant is the metal block when it is immersed in water?
What is the volume of the metal block?
What is the density of the metal block?
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1. Buoyancy = 54-34 = 20n = 2kg
2. Buoyancy = volume of water drained by metal ball × density of water = volume of metal ball × density of water
That is: 2 = V × 1, ｛ v = 2DM & ｛ 179;
3. Density = weight / volume = 54 / 2 = 27 n / decimeter & # 179; = 2.7 kg / decimeter & # 179;

Given that the three sides of a right triangle a, B, C (C is the hypotenuse) form an equal ratio sequence, then what is a: C (solution method)

According to known, B / a = C = B. that is, B ^ 2 = AC, by Pythagorean Theorem A ^ 2 + B ^ 2 = C ^ 2, simultaneous 1,2, AC = C ^ 2-A ^ 2, both sides divide C ^ 2, get (A / C) ^ 2 + (a / C) = 1, the solution is a / C = (- 1 + 5 under the root) / 2. It should be very clear!

The wood block with the mass of M1 = 4kg is stacked on the wood block with the mass of M2 = 5kg, and M2 is placed on a smooth horizontal plane
When M1 starts to slide with respect to m2, the horizontal pulling force F1 on M1 is 12 n. then, how much pulling force F2 should be applied to pull m2 to make M1 start to slide with respect to M2?

F1 is the maximum static friction of M1
(f2-f1) / m2 = F1 / M1, the solution is F2 = 27N

How to calculate growth rate with negative number

As with a positive number, the reduction is divided by the planned or previous year's amount

A small block with a mass of M = 0.5kg is placed on a horizontal turntable, the distance from the rotating shaft is r = 0.1M, and the dynamic friction coefficient between the block and the turntable is μ = 0.4
(1) When the angular velocity of the turntable is 1 rad / s, the friction force on the block is small;
(2) When the rotary table rotates at an angular velocity of 3rad / s, the block is subjected to external force;
(3) What is the maximum rotation angular velocity of the turntable in order to prevent the block from sliding on the turntable?

The centripetal force is provided by friction. So the centripetal force is equal to friction
(1) Centripetal force F = w ^ 2rm = 1 * 0.1 * 0.5 = 0.05N
The friction is 0.05N
(2) When rotating at a constant speed, gravity counteracts the supporting force, and the combined force is the friction force, that is, the centripetal force
External force F = w ^ 2rm = 9 * 0.1 * 0.5 = 0.45n
(3) The maximum angular velocity requires the maximum centripetal force, that is, the maximum static friction
f=μmg=0.4*0.5*10=2N
w^2=f/(rm)
W = 2, 10 rad / S

It is known that SN is the first n term of sequence {an} and the square of A1 = 1 Sn = n multiplied by an to find the common term of sequence {an}

Sn-S(n-1)=An=An*n^2-A(n-1)^2
It is reduced to an / [a (n-1)] = (n-1) / (n + 1)
A2/A1=1/3 A3/A2=2/4.An/A(n-1)=(n-1)/(n+1)
The multiplication of each term yields an / A1 = 2 / [n (n + 1)]
So an = 2 / [n (n + 1)]