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How to deduce the period formula of simple harmonic motion of spring oscillator?
In the process of moving, the force acting on the spring oscillator is proportional to the displacement, and the direction is opposite. F = - KX. That is to say, the force acting on the spring oscillator is a variable force. However, it is still true (Niu II). [x0df = ma = - Kmx] using the knowledge of higher numbers, it can be deduced that the spring oscillator is a periodic motion
If the length of a triangular pyramid is equal to that of the two edges, and the lengths are root 5, root 10 and root 13 respectively, then the volume of the circumscribed sphere of a triangular pyramid is?
The triangle pyramid can be inlaid into the cuboid, so that the diagonal length of each side is root 5, root 10, root 13, the cuboid edge length is a, B, C, then a ^ 2 + B ^ 2 = 5, a ^ 2 + C ^ 2 = 10, C ^ 2 + B ^ 2 = 13, and the three formulas are added to get a ^ 2 + B ^ 2 + C ^ 2 = 14, the cuboid diagonal length is √ 14, and the circumscribed sphere radius is r, then 2R = √ 14, r = √ 14 / 2
A little difficult
Subtract a natural number from 29 / 43, add the sum to the denominator, divide the fraction into 3 / 5, and find the natural number
(29-x)/(43+x)=3/5
5*(29-x)=3*(43+x)
145-5x=129+3x
8x=16
X=2
So the natural number is two
Given the expression of a sinusoidal alternating current, find the maximum value, period, frequency and initial phase
i=2sin(314t-45°)
The general formula of alternating current is as follows:
I = im * sin (WT + a), IM is its maximum amplitude, W is the angular frequency, and a is the initial phase
We know:
The effective value is 0.707 * IM, that is, the amplitude divided by the root 2
T=2Pi/w
The amplitude is 2 and the angular frequency is 314
The correct answer can be obtained by substituting the corresponding value into the above formula
Maximum im = 2A
Period T = 2pi / w = 0.02s
Frequency f = 50 Hz
Initial phase - 45 degrees
If two of the edges of a tetrahedron are 2 and 3 in length and the rest are all 1 in length, its volume will decrease______ .
Draw the figure from the title meaning, PA = Pb = PC = BC = 1, ab = 2, AC = 3, so △ ABC is a right triangle, O is the midpoint of AC, Po is vertical to the bottom ABC; it is easy to know that Po = 12; the volume of triangular pyramid is: 13 × 12 × 1 × 2 × 12 = 212, so the answer is: 212
A natural number is subtracted from 27 / 43 of the numerator. The denominator plus the natural number is about 5 / 9. What is the natural number?
（27-x）/（43+x)=5/9
5（27-x)=9(43+x)
-14X=252
x=-18
Are you sure you're right?
What is the conversion condition between AC motor and alternator?
If the power angle lags behind, it is the motor, if the power angle is ahead, it is the generator
If you think my answer is more satisfactory, because the adoption of the answer is the driving force for us to work tirelessly for it!
Electric motor is the conversion of electrical energy into magnetic energy, and then into mechanical energy. A generator converts mechanical energy into electrical energy. Well, I know.
Given that the edge length of tetrahedron is 1,1,1,1 and the root sign is 2, the maximum volume of tetrahedron can be obtained?
The bottom three sides of this tetrahedron are 1, 1 and 1. This is an isosceles right triangle, and the bottom area is s = √ 3 / 4
At this point, the other two edges are 1 and 1
This figure is the combination of equilateral triangle and isosceles right triangle
When the length of the last side is √ 2, the volume is the largest
V=(1/3)×(√3/4)×1=√3/12
Subtract the same natural number from the numerator and denominator of 29 out of 35 at the same time to get 3 out of 5
Twenty
(35-x)/(29-x)=3/5
Is there any conversion relationship between AC voltage, current and power? How to convert? I hope to give a conversion formula
P = UI = I2R = U2 / R is the same as that of DC. What we use to calculate is the effective value
RELATED INFORMATIONS
- 1. Suppose that the lengths of six edges of a tetrahedron are 1, 1, 1, 1, 2 and a respectively, and the edges with length a are different from those with length 2, then the value range of a is___ .
- 2. The numerator and denominator of a true fraction are two consecutive natural numbers. If the denominator is added with 4, the fraction will be about two-thirds of the following. It turns out that the fraction is many
- 3. How to calculate the formula of velocity in physical formula? What's the difference between velocity and average velocity
- 4. Given that P is a point in the plane of △ ABC, and PA + Pb + PC = 0, PA · Pb = Pb · PC = PC · PA = - 1, what is the area of △ ABC? There are vector symbols on the letters and zeros above ① From PA + Pb + PC = 0, we can prove that P is the center of gravity, but can we further find that △ ABC is an equilateral triangle? Why? ② From PA · Pb = Pb · PC = PC · PA = - 1, can we prove that P is perpendicular, and can we find that △ ABC is an equilateral triangle by combining with (1)? Also, the area is available on the Internet According to the meaning of the question, the triangle is an equilateral triangle, point P is the center of the triangle, and the distance from P to the three is √ 2. The solution is s = (3 √ 2) / 2 How to find it? How to get it? It seems that the title does not mention data. Is it found by PA · Pb = Pb · PC = PC · PA = - 1 and the triangle is an equilateral triangle? How to find it?
- 5. A fraction divided by an integer (except 0) equals______ .
- 6. How to change between angular velocity and rotational speed
- 7. P. If the volume of two points a and B on the sphere is vertical, then a and B are both vertical
- 8. Fractional addition and subtraction 3/x+1-3x/x+1=
- 9. What is the relationship between mass, orbit radius and centripetal force in binary system?
- 10. If each vertex of a regular octahedron with a surface area of 23 is on the same sphere, the volume of the sphere is___ .
- 11. One part plus one part plus one part plus one part plus one part plus one part equals one, fill in different natural numbers
- 12. In the quadrilateral ABCD, ab = ad = CD = 1, BD = radical 2. BD ⊥ CD. The quadrilateral ABCD is folded into tetrahedral a'bcd along the diagonal BD Let plane a 'BD ⊥ plane BCD, then the following conclusion is correct () A. The angle between a'c ⊥ BD B, Ca 'and plane a'bd is 30 ° C, and the angle ba'c = 90 ° D. the volume of tetrahedral a'bcd is 1 / 3
- 13. Verification: the frequency of simple harmonic motion is independent of amplitude Why is the frequency of simple harmonic motion (spring oscillator) only related to the mass and stiffness coefficient of the ball
- 14. Can the sum of several continuous natural numbers be equal to 1991?
- 15. If the edge length of a square is 1, the surface area and volume of the sphere tangent to each edge of the cube are?
- 16. Is the image of inverse scale function y = K / X axisymmetric? If so, how many axes does it have? Can you write the expression of the axis of symmetry?
- 17. If you subtract a from the numerator of the fraction 5379 and add a to the denominator, the natural number a equals 47______ .
- 18. If we know that the volume of the circumscribed sphere of a cube is 323 π, then the edge length of the cube is equal to () A. 22B. 233C. 423D. 433
- 19. It is known that f (x) is a periodic function with period 1. On [0,1], f (x) = x ^ 2. Find the expression of F (x) on [0,2] Don't copy f(x)=x^2 0≤x
- 20. The meaning of fraction subtraction is the same as that of integer subtraction The meaning of fraction subtraction is the same as that of integer subtraction The meaning of fractional addition is the same as that of integer addition Well, I'm stupid. Don't write too much in the space. I won't be able to do it=