What is the rotational speed of the earth

The angular velocity of the earth body rotating from west to east around the rotation axis passing through its center of mass is generally expressed as ω. Except that the pole is 0, its velocity is one twelfth of π (radian corresponding to 180 degrees) radians per hour. In WGS84 coordinate system, ω e = 7 292 115e-11 ± 0.1500 E-11 (rad / s)

The concept of earth rotation velocity
Such as the title

Angular velocity is the rotation angle of an object in circular motion per unit time
About 15 ° per hour, 1 ° every 4 minutes
The rotation speed of the earth's surface is the same at any place except the north and South points

5. As shown in the figure, the uniform thin rod OA can rotate around a horizontal fixed smooth axis with one end o perpendicular to the rod, so that the rod can fall freely from the horizontal position from rest. In the process of the rod swinging to the vertical position, the following statement is correct:
(A) The angular velocity increases from small to large and the angular acceleration increases from small to large;
(B) The angular velocity increases from small to large and the angular acceleration decreases from large to small;
(C) The angular velocity is from large to small, and the angular acceleration is from large to small;
(D) Angular velocity from large to small, angular acceleration from small to large
Picture above & nbsp; just forgot
Added

I don't know if you learned the concept of moment, M = rxfsina = ja
Where j is the moment of inertia, because the moment is decreasing, so the angular acceleration is decreasing, but the angular acceleration is still positive, that is to say, the angular velocity of the rod increases when the acceleration decreases

Sinusoidal alternating current means_ And_ All by_____ Changing current

Sinusoidal alternating current refers to the current or voltage whose size and direction change according to the sinusoidal law

Oscillogram of sinusoidal alternating current
It is known that the maximum value of a sinusoidal electromotive force is 220 V, the frequency is 50 Hz, and the initial phase is 300 degrees. Try to write out the analytical formula of this electromotive force, draw the waveform, and calculate the instantaneous value when t = 0.01 s
How to draw the key?

The graph is easy to draw. Now the data have been given to you. The maximum value is um = 220 v. from the frequency, we can know that the period T = 1 / F = 0.02 s. The initial phase angle should be changed into an angle within 180 degrees, that is, φ = - 60 degrees. We know that the graph with the initial phase angle of 0 degrees, plus the initial phase angle, that is, to move the graph horizontally to the left by 60 degrees. Originally, it was the maximum value at 90 degrees, but now it is the maximum value at 90-60 = 30 degrees, When 180-60 = 120 degrees, the value is 0,

The frequency of a sinusoidal alternating current is 50 Hz, the effective value is 5 A, and the initial phase is 5 degrees. Write its instantaneous time value expression and draw its waveform

Instantaneous value expression I (T) = v2x5xsin (2x3.14x50xt + 5x3.14 / 180)
Where: V 2x 5 is the maximum or peak value; 2x 3.14 x 50 is the angular frequency; 5x 3.14/180 is the conversion of 5 degree electric angle into radian
It is inconvenient to draw the waveform. It is a standard sine wave, but it can be shifted 5 degrees to the left

After the electric blanket is heated to a certain temperature, due to the action of P, the input sinusoidal alternating current can pass only half a cycle, that is, the voltage becomes the waveform shown in Fig. 58

It should be about 0.45 times u half wave rectifier 78V

There is a oscillogram of alternating current, which is a trigonometric function graph of time and voltage value. What will you get from this graph? Power? Or?

The product of the average voltage and the time between the upper and lower limits of the integral is obtained

The effective value of alternating current is defined according to. For sinusoidal alternating current, its effective value is the sinusoidal current whose peak frequency doubling rate is 50 Hz,

The effective value of alternating current is defined according to (thermal effect of current). For sinusoidal alternating current, its effective value is a sinusoidal current whose frequency doubling rate (√ 2 / 2) of peak value is 50 Hz,

How many times does the direction of 50 Hz alternating current change per second? How many times does the direction of sinusoidal alternating current change in a cycle?

50 Hz alternating current changes direction 100 times per second!
Sinusoidal alternating current changes direction twice a cycle!
He does sinusoidal change at 220 / 0 / - 220 / 0, the speed of change is 50 times / second (i.e. frequency is 50 Hz), and the polarity of each cycle changes from positive to negative and then to positive, twice

What is the rotational speed of the earth