What do you use to introduce others

What do you use to introduce others

This is that is singular
The plural uses those are those are

Given that the complex z = A-I / 1-I (a is greater than 0), and the difference between the imaginary part and the real part of the complex w = Z (Z + I) is 3 / 2, we can find the complex W

W = Z (Z + I) = (A-I) / (1-I) * [(A-I) / (1-I) + I] = (A-I) / (1-I) * (a + 1) / (- 2I) = (a + 1) (A-I) / (- 2I) = (a + 1) (AI + 1) / 2, so the difference between its imaginary part and its real part is (a + 1) a / 2 - (a + 1) / 2 = 3 / 2 (a + 1) a - (a + 1) = 3 (a + 1) (A-1) = 3A ^ 2 = 4A = 2 (a = - 2)

The efficiency of diesel engine can be calculated by the following formula: power 8800w, speed 2000r / min, fuel consumption rate 0.27kg/kw · h, cylinder number 1
It's mainly about how to find m and W,

Let the diesel engine work for t hours w = Pt, so w = 8.8kw * t h = 8.8t (kW · h) = 3.168 * 10 ^ 7T (J) m oil = w = 0.27kg/kw · H = 8.8t (kW · h) * 0.27 (kg / kW · h) = 2.376t (kg) w total = m * q (combustion value of diesel) = 2.376t (kg) * 3.3 * 10 ^ 7 (J / kg) = 7.84 * 10 ^ 7T (J / kg) =

It is proved that a & # 178; - AB + B & # 178; ≥ 0

Certification:
∵a²-ab+b²
=a²-ab+(1/4)b²+3/4b²
=(a-1/2b)²+3/4b²
And ∵ (A-1 / 2b) &# 178; ≥ 0,3 / 4B & # 178; ≥ 0
∴a²-ab+b²≥0

The resistance of the winding coil of a DC motor is 8 Ω. When it is connected to the 110V circuit and works normally, the current passing through is 2A. If the friction between the motor shaft and the bearing is neglected, the electric energy consumed by the motor in 1min is_____ J, where the conversion to mechanical energy is___ J

13200J,11280J

With a 15.7-meter-long rope around a tree for 10 times, how many meters is the diameter of the tree?

15.7 ﹣ 10 ﹣ 3.14 = 1.57 ﹣ 3.14 = 0.5 (m) a: the diameter of this big tree is 0.5 m

In the international system of units, the basic unit of length is

In the international system of units, the basic unit of length is the meter
The sign is m
When using any kind of measuring tool, we must first understand its measuring range and graduation value

The mass of object a is 1 kg, the mass of board B resting on a smooth horizontal plane is M2 = 0.5 kg, and the length is L = 1 m. at a certain time, a slides on the upper surface of board B at the initial speed of V0 = 4 MGS. In order to prevent a from sliding from B, a horizontal right pull f is applied to B while a slides on B. if the dynamic friction coefficient between a and B is 0.2, the condition that the pull F should meet is tried. (ignoring object a) (g = 10m / S2)

After sliding on board B, object a decelerates uniformly. According to Newton's second law, the acceleration is AA = μ G ① The acceleration motion of board B is F + M 1 g = m 2 ab ② When a reaches the right end of B, a and B have the same velocity V1, then: V02 − v122aa = v122ab + L ③ Also: V0 − v1aa = v1ab ④ If f ＜ 1n, then when a slides to the right end of B, its speed is still greater than that of B, so it will slide from B, so f must be greater than or equal to 1n. When f is larger, before a reaches the right end of B, it will have the same speed as B, and then a must be stationary relative to B, so it will not slide from the left end of B F = (M1 + m2) a, μ m1g = m1a, so: F = 3N, if f is greater than 3N, a will slide down to the left relative to B. therefore, the condition of tensile force F is 1n ≤ f ≤ 3N

How to calculate the land area?

1 mu = 60 square feet, 1 meter = 10 feet, 1 meter = 3 feet
For example: a piece of land is 50 * 20m = 1000m2, which needs to be multiplied by "15" coefficient = 1.5mu

A metal block with a gravity of 14.7n is suspended under the spring scale. When the metal block is immersed in water, the indication of the spring scale is 9.8N, then: (1) what is the buoyancy of water on the metal block? (2) What is the volume of boiled water discharged from the metal block?

(1) F floating = g-g1 = 14.7n-9.8n = 4.9n. A: the buoyancy of water on metal block is 4.9n. (2) V row = f floating ρ g = 4.91000 × 10m3 = 4.9 × 10-4m3. A: the volume of water discharged by metal block is 4.9 × 10-4m3