Fourth grade volume two Chinese unit 2 exercises - talk about the heart, about 400 words There should be a story!

Fourth grade volume two Chinese unit 2 exercises - talk about the heart, about 400 words There should be a story!

Mom, I love you. You brought me up. I'll never forget your kindness

How to write a composition in unit 2 of Volume 2 of primary school Chinese

Mom, I want to tell you

Grade 4 Volume 2 Chinese unit 2 composition

1, mom, mom, I have a lot of words to say to you, but I don't have the courage, I know, you may not wait for me to say, you will scold me. I have been in the grievance. This time I borrow our composition to tell you! I don't know why, I always think you are eccentric, you always

There are two figures: (1) there are n identical bulbs connected in series with R1 and connected in circuit; (2) there are n identical bulbs connected in series with R2 and connected in circuit; the voltage at both ends of the circuit is the same as u, and R1 and R2 are adjusted respectively to make all bulbs light normally, then the total power ratio of the two circuits (1) and (2) is -
The above is the topic. Originally, there was a picture, but I didn't know how to draw it, so I wrote it. I hope you can understand it. Please write the calculation formula when you answer it,

Comparing the two circuits, if n lamps are normal and the lamps are identical, the power of the lamps is equal in both cases, and the current passing through each lamp is equal to the voltage of each lamp
Set the normal working current of each lamp as I1
The comparison is the total power, depending on the total voltage and total current
The total voltage is u
What is the total current through the first circuit
I total 1 = Ni1 because there are N parallel branches to be added
What is the total current through the second circuit
I total 2 = I 1, because no matter how many series, the current is one
So, the power ratio is
P1 / P2 = u * I total 1 / u * I total 2 = n
The answer is n

Is projection a quantity or a vector?
ditto

Quantity

A complete collection of calculation formulas for junior high school physics

Mass m kg kg m = PV temperature T ° C velocity v m / S v = s / T density p kg / M? Kg / M? P = m / V force (gravity) f Newton (Newton) n g = mg pressure P Pascal (PA) P = f / s work w Joule (joule) J W = FS power P watt (watt) w

When the amplitude is a, the maximum pressure of the object on the spring is 1.5 times of the weight of the object
When a is at the highest point, gravity minus elastic force is equal to the resultant force, but at the highest point, the elastic force should not be downward (because the elastic force of the spring points to the direction of restoring the free length of the spring), but according to the solution, the problem is upward. Please tell me more about it. I don't know about these elastic forces

When doing simple harmonic motion, the spring does not have to compress or stretch for a while. In this problem, it is all compression. When the amplitude is reached, the maximum pressure of the object on the spring is 1.5 times of the weight of the object, indicating that the restoring force is 0.5mg, so at the highest point, the restoring force should become a downward force, the size is 0.5mg, so the elastic force upward is 0.5mg
It must be noted that the restoring force is the resultant force along the vibration direction. It is correct to think from the perspective of providing restoring force

How much J is 1kW * H?

1kw*h=1000W×3600s=3.6×10^6J

Use balance and spring dynamometer to weigh the same object on the earth and the moon respectively. The result of weighing is ()
A. The weighing results of balance and spring dynamometer are the same. B. the weighing results of balance are different, and the weighing results of spring dynamometer are the same. C. the weighing results of balance are the same, but the weighing results of spring dynamometer are different. D. the weighing results of balance and spring dynamometer are different

(1) If the balance works under the condition of lever balance, the mass of the object and the weight remain unchanged, and the gravity becomes the original 16. The lever is still balanced, so the measured mass remains unchanged, so the measurement results are the same. (2) the gravity of the object from the earth to the moon becomes the original 16, the tension of the object on the spring becomes the original 16, and the indication of the spring dynamometer becomes the original 16 16, so the measurement results are different

Is the perimeter and area of a square a function?

Yes
Let the perimeter be x and the area be s, then s = (x / 4) & sup2; be known from the square of the area equal to the side length, where the domain of definition of the independent variable x is (0, + ∞). With the analytic formula and domain of definition, then the perimeter and area of the square are functions