About a physics problem, the topic is very simple, I just can t figure it out a little bit? 30

Your biggest vulnerability is that you need the vehicle to maintain a constant linear motion, and if there is an acceleration, the drone will hit the wall.

Start the drone in the train, if the acceleration of the train is 0, the drone will remain relatively stationary with the train at this time, if the train is accelerating or decelerating at this time, it will hit the wall, because the speed of the drone is at the moment of leaving the contact with the carriage, and the speed of the train is changing, and the plane is the same.

If you want to achieve the scenario 2 you want, you need to connect the drone and cargo with the vehicle when you start, wait for the vehicle to reach the specified speed before suspension, and then end the suspension before the vehicle slows down, and the drone and the cargo are required to be in the confined space inside the vehicle, not affected by the outside air, and the vehicle cannot change the direction of travel and altitude in the process, that is, the acceleration of the vehicle in all directions needs to be 0

The drone hovering on the train will not go with the train and will be pulled down relatively.

The question about a physics problem is simple. I just can't figure it out. Then you can think again. I'm sure I'll be able to figure it out for him.

About a physics problem, the question is very simple, but there is a little bit of incomprehension, I don't think it can be figured out, that means that you are now drilling the horns, in fact, you know how to do this problem, I suggest you still think about it.

About a physics problem, the topic is very clear and simple, I just can't figure it out, there are many things that I can't figure out, and it's even more the same about physics.

Have you ever considered that the air inside the train is also moving forward? Why don't you put a drone on the roof of the train?

Regarding a physics problem, solid wood is so simple, I just can't figure it out?

For a physics problem, the topic is very simple, but it is a little difficult to figure out.

I just suddenly thought of a question, in fact, according to junior high school physics.

It really can't be done without a complete and independent personality. That would not be complete and feasible at that time.

Summary. Related information: The RMS value is specified according to the thermal effect of the current, so that an alternating current and a DC current pass through a resistor with the same resistance value, if the heat generated in the same time is equal, then the value of this DC is called the RMS value of the alternating current.

In electrotechnology, it is not always necessary to know the instantaneous value of alternating current, but to specify a specific value that characterizes its magnitude – the effective value, based on the fact that when both AC and DC currents pass through the resistance, the resistance consumes electrical energy (thermal effect).

In addition to the same amount of heat generated, can you use the same amount of electricity that passes?

**Didn't shoot all the pro.

I mean, in addition to this practice, can you do it by equalizing the amount of electricity.

Let Xiaomei do the math first.

Xiaomei thinks that the first half of this picture is divided into alternating current, and the second half of Brother Shimin is direct current, and the method of equal electricity may not be too good, and the best solution should be deduced through definitions.

Related information: The RMS value is specified according to the thermal effect of the current, so that an alternating current and a DC current pass through the resistance of the same resistance value respectively, if the heat generated in the same time is equal, then the value of this DC is called the RMS value of the alternating current. In electrotechnical technology, it is sometimes not necessary to know the instantaneous value of alternating current, but to specify a specific value that can characterize its size, the effective value, based on the fact that when both the alternating current and the direct current pass through the resistance, both the electric energy (thermal effect) is consumed.

q is equal to it, and the effective value is multiplied by half of t, followed by the constant current multiplied by a quarter of t, which is equal to the total amount of electricity, and then divided by time.

Let Xiaomei look at this question according to your thoughts.

By judging Ruzi, Xiaomei also feels that this Sidan Rubber Cave Road is feasible, but will the error be due to the wrong data? Or there are some places that we haven't noticed, Xiaomei's suggestion is to start from the definition, after all, the solution is more intuitive in the final analysis.

It should be selected that when an object is in a certain state, it cannot be said how much heat it contains (heat is the amount of process, equivalent to delta).

In the case of A, the reduction of temperature and specific heat capacity is not considered.

The landlord's answer was wrong. The correct answer is: c.

Heat is the energy absorbed or emitted by an object in the process of temperature change, and it reflects the energy transfer of a change process, so heat can never be described by the word "containing".

When blowing, it is the column of air inside the tube that vibrates.

When striking, it is a system of test tubes and water that vibrates.

Obviously, the amount of water increases, the mass of the vibrating object decreases, the natural frequency increases, and the corresponding tone rises; The mass of the latter vibrating object increases, the natural frequency decreases, and the corresponding pitch decreases.

The question is as follows: du

y= vt - 1 2 g t 2 physically means that zhi throws an object dao with v as the initial velocity, as opposed to the object when it is thrown.

The formula for calculating the displacement (rising height) of the position (height) of the answer point.

v is the initial velocity, g is the acceleration due to gravity, t is the time elapsed after throwing, and y is the height.

You may not have gone to high school, you will learn it in high school, this is the formula of linear motion with uniform variable speed, which is very important, and similar questions in the college entrance examination are required.

You can look up this physics problem in the book.

In fact, it is not **, but due to the action of gravity, it moves downward, and if it is balanced or not, it will always maintain a uniform linear motion. But this is only an assumption, and it is not yet possible to reach the point of not being forced, so it is impossible.

The increased BAI mass 224-190=34 is the mass of the reduced water plus the increased mass of the genus Du, then the internal mass of the water with less DAO = PV (P represents the density of the water, V is the reduced volume), you can find the volume of the reduced water = the volume of the metal block, the density of the metal = the mass volume, which can be found.

This is because the real image is formed by the intersection of the actual light, and the virtual image is the intersection of the extension of the actual light (sometimes in reverse). In addition, the real image can be carried over with a light screen, while the virtual image can only be seen with the eyes.

1.If you add the horizontal to the right bai pull force f=27n, just pull the wooden block zhi, find the maximum static friction dao friction force on the wooden block. Back to 27n2If the horizontal tensile force f=25n, the wooden block is just moving forward at a uniform speed, and the kinetic friction factor is 25 10*10=

3.If the block is stationary, when the horizontal thrust f=26n, how much friction is the block?

26. If the wood is moving fast, when the horizontal thrust f=26n is still added, how much friction is the wood block? 25

The temperature of the ice water mixture is 20 degrees when measuring DU, and the temperature of boiling water is 80 degrees at a standard atmospheric pressure, indicating that the range of 60 degrees of the temperature weight represents 100 degrees.

The thermometer shows 41 degrees Celsius, and the actual temperature corresponds to that.

41-20)/60=x/100

x = 35 degrees.

The number of the thermometer when the actual temperature is 60 degrees.

x-20)/60=60/100

x = 56 degrees.

This problem can be solved by copy force analysis. First of all, for the whole, if it is all the force of five ox, whether the spring is in equilibrium (or stationary), then whether the reading of your spring is the force of the stretchable section, that is five ox. In the second case, there are five oxen at one end, then the spring must be moving, so how can there be a reading.

In the third case, although the spring is moving, is the force on the part where it is stretched!!

For this kind of problem, you have to build a physical model, which is a problem of connecting bodies, that is, two objects are connected by a thin line or something, then the acceleration of the motion of these two objects must be the same, then it can be solved according to Newton's second law!

Depending on the nature of the rope, if it is not extensible, then the force at both ends of the rope is equal when it is at rest, and the tension of the rope during movement should be the resultant force; If the rope is extendable, such as a spring, then the forces at both ends of the rope should be equal according to Newton's third law.

Radians and angles are similar.

It represents the size of a corner.

The unit of radians is rad

The conversion relationship between the two is 360 degrees = 2pai

The arc length is the length of a circular arc.

l=a*r, where the central angle a should be expressed in radians.

The formula l=(n 360)*2pai*r is used for angles

The quality is large, and bai can be du from some of the experimental problems done

In order to find that the square of the resistance and velocity of the air qi is positive

ratio, which is inversely proportional to the area, and the answer to the area in the question does not need to be considered. The gravitational potential energy with a large mass is relatively large, while the work done by the air resistance is approximately equal when the velocity of the two objects is not much different, so the work done with the mass is earlier.

The rate of motion of a molecule generally has a range distribution.

However, under the condition of stable external conditions, the distribution of the rate version is constant, that is, the proportion of the sum of the molecules of a certain rate in all molecules is constant. The statistical graph of the rate distribution is the relationship graph that expresses this ratio, the horizontal axis is the rate range, the vertical axis is the probability density distribution, and the physical meaning is that the percentage of the number of molecules in the range and the total number of molecules in a small range near the velocity is obtained by the product of the probability density at the point and the velocity amplitude of this small range.

The volume of water measured when upright is bai, there is v water = d 2 (4l1).

The volume of air is measured in the inverted handstand, with daov = d2 (4l2).

And the volume of water is known to us, so the volume of the bottle v = v water + v gas = d 2 (4l1) + d 2 (4l2).

Because the temperature is low, the water condenses into ice, and the density of the water is greater than the density of the ice, by the formula volume = mass density, the mass remains the same, the smaller the density, the larger the volume, so the volume of water condenses into ice, and the water pipe is cracked.

Thermal expansion and cold contraction

1] is a basic property of an object, the object in the general state zhi dao , after being heated will expand, in.

When the version is cold, the rights will be reduced. All objects have this property.

Note: Water above 4 will expand and contract, and below 4 will expand and contract. When it comes to ice, the density is only. This means that the ice will float on the surface. Substances such as antimony, bismuth, gallium, and bronze shrink when heated in certain temperature ranges and expand when cold. ）

Objects expand when heated and contract when cold. This is due to the fact that the motion of particles (atoms) in an object changes with temperature, and when the temperature rises, the vibration amplitude of the particles increases, causing the object to expand. However, when the temperature drops, the vibration amplitude of the particles decreases, causing the object to shrink.

Objects have the phenomenon of thermal expansion and cold contraction, and we can use this phenomenon to solve some difficulties in daily life.

The vast majority of substances in nature follow the law of "thermal expansion and cold contraction", with few exceptions. One exception is water. Water is the densest at 4, and below 4 it is abnormally expanding, which is "heat shrinkage and cold expansion". And to the ice, the density is.

Only. This means that the ice will float on the surface.

It's not the glass that's the property, it's the film that sticks to the outside of the glass.

That layer of film is better for the unilateral orientation of the light version. That is to say, it is very difficult to pass it in, but it is easier to pass it out!

So when you look outside, it's hard to see what's inside, but if you're close to the outside, you can see what's inside!

Solution: The glass is coated with a layer of anti-reflection coating to increase the reflection of external light.

Yes, no matter how fast you are, as long as it is a constant velocity, you can know that the acceleration is zero, and the pulling force and friction force are equal!

Is there friction on the ground? If so, is the coefficient of friction the same? If there is no friction, A is 3 times that of B!

When disconnected.

R1 and R2 are connected in parallel, and the current of each share is .

i has 2i*r2=(3i-2i)*r1

2r2=r1

When closed, R1, R2 are connected in series.

U A is the total voltage, and u B is the voltage of R2.

Follow the voltage division of the series circuit.

U A: U B = 3:1

Paper and wood are generally insulators, and if they are surrounded by energized wires, they can be magnetic. However, it is not wood or paper that produces magnetism, it is essentially the magnetic effect of electric current, which can be found in the chapter on learning magnetic fields in high school textbooks.

Hello, this is inaccurate, the light density and the light phobic medium are not related to the density! Due to the refractive index, the propagation speed is different!

c kWh = 1 kWh.

Multiply two times less than or equal to 1000.

The point o is zero, and from the point o to the horizontal line and the vertical bisector line are from (zero) small to large and then small to zero.