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A resistance R to be measured and current a are connected in series in the circuit shown in the figure. At this time, the indication of the ammeter is I1. If a constant resistance R0 with known resistance value is connected in series in this circuit, the indication of the ammeter becomes I2. According to the above data, the resistance value of the resistance Rx to be measured can be obtained——
(Rx+Ro)*i2=Rx*i1
Rx*i2+Ro*i2=Rx*i1
Rx*i1-Rx*i2=Ro*i2
Rx*(i1-i2)=Ro*i2
Rx=Ro*i2/(i1-i2)
Seeking the understanding of Newton's second law
The acceleration of a body's motion is directly proportional to the combined external force and inversely proportional to the mass of the body. Its formula is: F = ma. It is the core formula of force and motion, that is, the core of dynamics. Equilibrium state is the state of static or uniform linear motion of the body. Overweight refers to the state in which the supporting force is greater than gravity. Weightlessness refers to the state in which the supporting force is less than gravity
A small ball has acceleration to the right, so how to get it? There must be a force to the right applied to it. After the small ball leans to the left, the resultant force of gravity and the upward pull of the rope is a horizontal right force, which gives the small ball acceleration to the right
The area of triangle is 15cm 2, the height is 5cm, and the bottom is () cm
The area of the triangle is 15 cm 2, the height is 5 cm, and the bottom is (6) cm
15×2÷5=6CM
Two people respectively pull the hook and ring of the spring scale with 100N force, and the reading of the spring scale is?
100N
The hook of the spring scale can be regarded as fixed at a point. If the ring is pulled with 100N force, the reading is obviously 100N
If you look at the fixed point at the hook of the spring scale, it is also under the tension of 100N. The force is mutual, so the hook is also pulled by the tension of 100N
Primary school four operations, must be four
The disk rotates around the fixed axis Z with uniform angular velocity W. the mass of the disk is m and the radius is R. what is the momentum of the disk? What is the moment of momentum?
The individual answer is: momentum is 0; momentum is j * W, where j = 0.5mr ^ 2~
Such as the title. The personal answer is: momentum is 0; momentum is j * W, where j = 0.5mr ^ 2. There is a reference answer: momentum = MRW, I think the answer is wrong, please expert advice~
If a straight rod (length L, mass m) rotates at a uniform angular velocity W around its end z-axis, the momentum should be MWL / 2. To put it bluntly, the momentum index is only related to the velocity at the center of the rigid body.
If the axis Z is perpendicular to the disk surface and passes through the disk center, you are right
Let an arithmetic sequence an, tolerance D ≠ 0, its first 10 terms S10 = 110, and A2 ^ 2 = A1 * A4, seek (1) verification: A1 = D (2) seek the value of tolerance D and the general formula of sequence an (3) seek the first n terms and Sn of sequence an
(1) A2 & # 178; = A1 * A4, so (a1 + D) × (a1 + D) = A1 × (a1 + 3D) is reduced to D & # 178; = A1 × D
Because D ≠ 0, A1 = D
(2) S10 = 110, that is, (a1 + A10) × 10 △ 2 = 110
And a1 + A10 = 2A1 + 9D, A1 = D is obtained from (1)
Substituting ①, 55D = 110, A1 = D = 2
an＝a1＋﹙n-1﹚×d＝2n
﹙3﹚Sn=﹙a1＋an﹚×n÷2＝n²＋n
This is a relatively simple sequence problem. It seems that you don't quite understand some basic concepts of sequence, so you should strengthen your practice. It is suggested that you don't send questions to the Internet as soon as you encounter problems that you can't do. You should think more about them
A car moves at a constant speed of V0 = 10m / s along a straight road, and suddenly brakes at an acceleration of 2m / S2. What is the average speed in the third second? ② What is the displacement within 6 seconds after braking?
(1) From v = V0 + at, the velocity at the beginning of the third second is V1 = 6m / s, and the velocity at the end of the third second is V2 = 4m / S & nbsp; So the average speed in the third second is: v = V1 + V22 = 6 + 42m / S = 5m / S (2) the time from braking to stopping is t0 = 0 − v0a = 0 − 10 − 2S = 5S ＜ 6S, so the displacement in 6S is equal to that in 5S. X = v0t0 + 12at02 = 10 × 5-12 × 2 × 25m = 25m
Xiaojun's distance is one fourth more than Xiaohong's, but Xiaohong's time is one tenth more than Xiaojun's?
The distance of Xiaojun is one fourth more than that of Xiaohong, and the ratio of Xiaojun to Xiaohong is 5:4;
Xiaohong spent one tenth more time than Xiaojun, and the ratio of time between Xiaohong and Xiaojun was 11:10;
Speed ratio = (5 / 10): (4 / 11) = 11:8
In the second semester of junior high school,
1、this is the our first French class.
2、don't forget calling him back when you see him.
3、I afraid she is still at home with her mum now.
4、I‘m afraid to late tomorrow.
5、how many people do live in your home?
6、we are twelve floors in the building.
7、there are none calories in water.
8、sandy will get in Beijing at 8 o'clock.
9、it's her the twentieth birthday today.
1. Remove the
2. Forget calling is changed to forget to call
3. I afraid is changed to I am afraid
4. To be late instead of to be late
5. Remove do
6. We changed to there
7. Change none to No
8. Change get in to get to
9. Remove the
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