Thank you very much what we need to do is ___ A.work hard B.working hard

working hard
The verb phrase can not be used as a predicative, it must be replaced by a gerund

Thank you very much!

Compared with junior high school, the vocabulary of senior high school English has increased greatly. On average, we have to recite 5,60 words after a lesson, and senior high school class is relatively difficult. Therefore, it is difficult to have energy to recite. However, if we can persist in reciting 15 words every day and reciting for a long time, the effect is far better than the surprise recitation before the exam. In addition to the number of words, senior high school pays more attention to

How to verify whether the lens is convex when the bulb has no parallel light source? Thank you very much. 0-

How to verify whether the lens is convex when the bulb has no parallel light source?
First of all, convex lens, also known as convergent lens, has a convergent effect on the transmitted light
The light of a bulb should radiate from the bulb and pass through the lens. Only when the bulb is at the focus F of the lens can the light become parallel
How to verify whether the lens is convex? Principle?
The convex lens has a converging effect on the transmitted light. Put it under the sunlight and use the light screen to receive it to see whether the light is divergent or converging
The principle should be refraction of light

Is Kirchhoff theorem the content of junior high school or senior high school
In a lumped parameter circuit, the current and voltage are subject to two kinds of constraints, because the interconnection between circuit components will inevitably force the connection or constraint between the current in the components and the voltage on the components. Kirchhoff's law is the embodiment of this constraint. (1) Kirchhoff's first law, also known as Kirchhoff's current law, is abbreviated as KCl, The first statement of KCl: for any node in any lumped circuit, at any time, the algebraic sum of all branch currents flowing out (or into) the node is zero. The second statement of KCl: for any closed surface in any lumped circuit, at any time, the algebraic sum of all branch currents flowing out (or into) the node is zero, (2) Kirchhoff's second law, also known as Kirchhoff's voltage law, abbreviated as KVL, is the embodiment of the single value of potential in lumped parameter circuit when the electric field is potential field, and its physical background is the axiom of energy conservation, The algebraic sum of all branch voltage drops along the loop is zero.13

It seems that the university just mentioned this theorem, but junior high school has already involved it

I know the high throw formula. How to calculate the wind force
Is the wind angle?

90 distance + / - wind x2 calculate distance: (it's the laughing map in the upper right corner. Pay attention to the map in the map. Think of the map as ten copies, and then move the white square to the small dot of you and the person you want to fight on the map. The edge of the white map should face your own small dot, and then estimate the distance of each other's small dot

The wind speed is v. what is the expression of wind speed?

V=0.84*F^(3/2)
V is the wind speed (M / s) and F is the Pu's scale
Wind rating 118

How to calculate the wind force?
It was windy last night, and I had to use a lot of force to open the door, so I suddenly thought of a question:
Suppose the wind direction is perpendicular to the door, and the force used to pull the door is 5N. How to calculate the wind speed v? How to calculate the force F applied to the door by the wind?
Thank you, Jim HXY
Can I explain the principle of Bernoulli equation and the parameter Rho a little bit? The equation I searched out is p + 1 / 2 ρ V2 = C, and I don't have any ready-made books to refer to

According to Bernoulli formula, for example, when the wind speed perpendicular to the object is 10m / s, the vertical wind pressure acting on an area of 1 square meter is:
p=1/2*rho*v**2 = 0.5*1.225*100 = 61.25 (N/m^2)
F=p*s=61.25*1.0= 61.25 N

Under what conditions will metal materials produce fatigue failure?

Fatigue failure is mainly caused by fatigue stress. Fatigue stress is the resistance of materials, parts and structural parts to fatigue failure. Under the specified cyclic stress amplitude and a large number of repeated times, the material can bear the maximum alternating stress. Fatigue failure is one of the main reasons for the failure of mechanical parts

Can any metal material produce photoelectric effect under illumination?

Yes. It depends on the frequency of the incident light. Any metal has a limit frequency. When the frequency of the incident light is greater than this limit frequency, photoelectric effect can be produced

What is metal fatigue and what are the characteristics of fatigue failure

Why metal fatigue will produce damage? This is because the internal structure of the metal is not uniform, resulting in the imbalance of stress transmission, some places will become stress concentration area. At the same time, there are many tiny cracks in the defects of the metal. Under the continuous action of the force, the cracks will become larger and larger, and the material can

Thank you very much what we need to do is ___ A.work hard B.working hard