Solve a physics problem in the second year of junior high school, find a physics problem in the seco

CA Answer: The velocity of A is 2m s

B Answer: The earth rotates from west to east, then the velocity of A is 2m s plus the speed of the earth's rotation is the true velocity of A with the sun as the reference.

Answer C If B is used as a reference, then A's velocity is -1m sdAnswer: Needless to say, I know that it is wrong, nothing is absolute, and the theory of relativity is clearly reflected If we take what is inside the object as a reference, then it is still stationary.

So the answer is C

is selected C, with object B as the reference, the velocity value of A is 1m s

Taking several other objects as a reference, the velocity value is greater than 1, and taking the sun as a reference, the velocity of A is very large, and the value is approximate to the speed of the earth.

First of all, I want to say that the question is wrong: 2m s and 3m s should be: 2m s and 3m s

A: Relative to the Earth, it is 2m s

b: The velocity of A is very large, and the value is approximate to the speed of the earth.

c: The velocity relative to B is 1m s

D: The speed of movement is relative, this option must be wrong!

Therefore, C. is chosen

If C takes B as the reference, then the velocity of A is 1m s to the east, and 2 m s to the earthNo matter how you choose, you won't get B. Because the earth revolves around the sun, how can it be possible to use the sun as a reference?

The concept is a bit confusing what exactly is relative velocity and what is absolute velocity, which should be stated in the stylistics. The absolute velocity of A is 2m s, but the relative velocity relative to B is -1m s, which is the smallest. But if the absolute velocity is asked, then the absolute velocity of A is 2m s, which is the velocity relative to the ground.

c Taking B as the reference, the velocity of A is 1m s

If the sun is taken as a reference, the velocity of A is the vector sum of the velocity of A to the earth and the velocity of the earth to the sun, which is about the speed of the earth and the sun, which is very large.

I think it's d, because it's the slower, whatever the reference is.

c is the correct answer. When B is used as a reference, A's velocity is -1m s

c, its velocity relative to B is 1m s, relative to the earth is 2m s, relative to the sun is larger, how big is the speed of the earth relative to the sun! The relative velocity of A is not the same depending on the reference!

…I think it's D, and no matter who you use as a reference, A's velocity is always the smallest.

It is C, B and D are clearly wrong, and it is not difficult to tell that A is wrong.

I support your answer.

Taking object B as a reference, the velocity of object A is 1m s, facing east; Or 1m s

c The relative velocity that we just learned, how could I not know, their relative velocity is 1.

Yes, you and your mom got it wrong.

Is there still a need to argue!!

1. By: Variable resistance p In the sliding process, the indication change of the voltmeter is 0-5V, and the indication change of the ammeter is.

The conditions can be known: the maximum resistance of the variable resistor p is 5 ohms. That is, when the voltage number is 5V, the ammeter is 1A, so the maximum resistance of the variable resistor P is 5 ohms.

2. Since the power supply voltage u is constant, the two equations of the maximum and minimum cases of p in the sliding process are obtained:

When rp=0, there is u=i1*r1=, and the loop current i1 is When rp=5, there is u=i2*r1+i2*rp=r1+5

In this case, the loop current i2 is 1A).

Because the supply voltage u does not change, the equation: =

i.e. r1=10

Ohm 3, the supply voltage u=15v can be obtained from the equation or

(1) Same.

Convex lens, into.

In the case of a real image, the image distance is v

It decreases with the increase of the object distance u. (2 points).

2) Object-screen distance l (1 point).

The object distance of the first image is the image distance of the second image. (1 point) (3) The object screen distance l is greater than 4 times the focal length of the convex lens. (2 points).