The rated voltage of the motor is 110V, the rated current is 2.2kW. The resistance of the coil is 0.5 ohm? We need to be quick`

The rated voltage of the motor is 110V, the rated current is 2.2kW. The resistance of the coil is 0.5 ohm? We need to be quick`

Rated current = rated power / rated voltage = 2.2kw/110v = 20A
Please accept if you are satisfied

It is known that a body starts to make a uniform acceleration motion from static state, and the velocity at the end of 5S is 3m / s, then what is the displacement of the body in the 5th s

a=(v5-v0)/t=3/5=0.6m/s2
The speed at the end of the fourth second is:
V4=a*t=0.6×4=2.4m/s
The displacement in the fifth second is:
S=（V4+V5）×t/2=2.7m

Is current the basic physical quantity in the international system of units

There are seven basic units: length m, time s, mass kg, thermodynamic temperature (Kelvin temperature) k, current unit a, light intensity unit CD (candela), and mass mol

A light spring with free length Lo is used to tie a small ball with mass m at one end and fix it at the other end to make the ball move uniformly and circularly on the horizontal plane
When the angular velocity of the ball is W1, the spring extends to 2lo. When the angular velocity of the ball is W2, the spring extends to 3lo. What is the ratio of W1 to W2

L1＝2L0 ,ΔL1＝2L0－L0＝L0；
L2＝3L0 ,ΔL2＝3L0－L0＝2L0；
Spring tension = centripetal force:
m*ω1^2*L1=k*ΔL1 ①；
m*ω2^2*L2=k*ΔL2 ②.
① / 2
ω1^2：ω2^2＝（ΔL1*L2）：（ΔL2*L1）＝3：4 .
So: ω 1: ω 2 = √ 3:2

How many acres is a hectare

One hectare is 100 meters long and 100 meters wide, which is 10000 square meters; one mu is 666.67 square meters. Therefore, the conversion relationship is 1 hectare = 15 mu

An iron ball is hung under the spring scale. The real number of the spring scale is 3.92 n. when the iron ball is completely immersed in water, the indication of the spring scale is 2.94 n
An iron ball is hung under the spring scale. The real number of the spring scale is 3.92n. When the iron ball is completely immersed in water, the real number of the spring scale is 2.94n, the known buoyancy is 0.98n, the volume is 1 * 10 ^ - 4m3, and the iron density is 7.8 * 10 ^ 3kg
Is the iron ball hollow or solid

7.8 * 10 ^ 3 * 1 * 10 ^ - 4 * 10 = 7.8 this is the gravity of a solid sphere
The gravity of the ball is 3.92 n
So it's hollow

Given the square of quadratic function y = 8x - (k-i) x + k-7, when what is the value of K, the quadratic function takes the Y axis as the axis of symmetry? Find out its functional relationship

The formula of the axis of symmetry is - B / 2A
To make it symmetrical on the Y axis
K=1
The square of y = 8x-6

As shown in the figure, the masses of wood blocks a and B are ma and MB respectively, and the friction coefficients with the horizontal ground are μ 1 and μ 2 respectively. The two wood blocks are placed on the horizontal plane, and they are connected by thin lines. In the case of two connections, the inclined direction of the thin lines is different, but the inclination angle is the same. The ratio of μ 1 and μ 2 is ()
A. 1:1b. Ma: MBC. MB: mad. Not sure

According to the equilibrium condition, f = FA + FB, FA = μ 1 (mag-t1sin θ), FB = μ 2 (MBG + t1sin θ), f = μ 1 (mag-t1sin θ) + μ 2 (MBG + t1sin θ) = μ 1mag + μ 2mbg - (μ 1 - μ 2) t1sin θ ① Same as

How to do negative multiplication
Take - 4 and - 7 for example

-4 x (- 7) = 28, negative is positive
-4 x 7 = - 28 negative, positive, negative
4 x 7 = 28

N = 3R and [(3R) (3r-1) (3r-2) How to solve (2R + 1)] / (r!) 2 ^ R = 60?

It's not necessary to solve the combinatorial number,
[(3r)(3r-1)(3r-2)…… (2r+1)]/(r!)=C(3r,r)
Just write it as a combination number, so it is
C(3r,r)*2^r=60=15*2^2
Note that C (3R, R) is a combinatorial number, which must be an integer, and there are only two factors 2 in 60
So the value of R must not be greater than 2, that is to say, R can only be 1 or 2
When r = 1, C (3R, R) * 2 ^ R = C (3,1) * 2 = 6, not satisfied
When r = 2, C (3R, R) * 2 ^ R = C (6,2) * 2 ^ 2 = 60
n=3r=6
When solving the combined number equation, we need to make good use of the condition that each number is an integer, and we don't need to solve it like the ordinary equation