Senior 2 Physics 3 1, masters, please enter!

1.Yes, electrostatic induction occurs. It is impossible to find out the force in high school. Each ball is charged q after contact

f2=rr, i.e. 1 12f

3.It has to be derived using calculus.

In this way, draw two parallel plates, one point at a certain distance on the upper plate surface.

Make the dots on the plates symmetrical. The dots on the two plates are then connected (which can be regarded as an electric field.

line) so that you will find that every line that is not perpendicular to the plate has another line with him.

Offset. Therefore, the electric field between the plates is a uniform electric field.

A large distance can be considered as a point charge. Unequal amounts, you add a little more points to a plate.

You know, the edge charge is not evenly distributed.

4.It is not a uniform electric field, and it does not meet the definition of a uniform electric field at all.

The electron orbital in the hydrogen atom is indeterminate and not a definite line.

Let's think about this question after studying structural chemistry in depth.

5.It is common to choose the zero point where infinity is the electric potential and the zero where the earth is often used.

Dot It's a habit. You can choose something else.

It is grounded, so plate A is the zero point of electric potential. The grounding potential of the positive pole of the power supply is 0, and B is connected to the negative pole, and the potential is less than A-36V; c:-12v

Take a look at the formulas in the book and look at a few more example problems! These dishes are all simple! Let others help with this kind of topic! No one will help you with your college entrance examination!

1.Yes, you can't ask for it, because the conditions are not enough.

Because, when the distance is r f = k*3q*q r 2, when the distance is 2r f = k*3q*q (2r) 2=k*3q*q 4r 2

So f=

The falling time is the time it takes for the child to accelerate from zero speed to the acceleration generated by the external force that accelerates the child from the speed of zero. That is, at =, where a=6m s running downstairs is the speed of the acceleration from 0 to the end of 9 meters in the above time, which is a't =9, v=a'The work done by the slow cavity ruler is to consume the child's kinetic energy, so this work is the work of the external force in the process of the child's fall.

This is equivalent to Wu Juping canceling the kinetic energy generated by Niu Niu's gravitational potential energy minus the energy of resistance. The work done by drag force is = 1140 (n*m) and the work done by gravity is 10* = 2850 (n*m), then the work done by Wu Juping is 2850 - 1140 = 1710 (n*m).

1) Use Newton's second law for Niuniu: Find: a1=6m s2 Niuniu's falling process is a linear motion with uniform variable speed, and the relationship between the start and side of the displacement time:

h1=12a1t2 solution: t=3s(2) Wuyun accelerated motion: s=12a 2t2 solution:

a2=2m s2 by the velocity-time relation: 2=a2t=6m s(3)The velocity of Niuniu's fall h1: Wu next to the high 1=a1t=18m s buffer process, for Niuniu by the kinetic energy theorem, get:

W+MGH2=0-12M 12W=-1770JAnswer: (1) The time when Niuniu fell before being picked up was 3s; (2) The speed of Wu Juping when she ran downstairs was 6m s; (3) In the buffering process, Wu Juping's work on Niuniu is -1770j

Calculate the velocity of Niu Niu when she is in order to find her kinetic energy, which is also = work done by gravity - work done by friction; Coupled with its potential energy, it is concluded that the final state of the initial state is that its velocity is 0 and the and potential energy is 0

1) Use Newton's second law for Niu Niu: Find: a1 = 6m s2 Niu Niu falls over the orange is a uniform speed straight.

2) Wuyun acceleration motion: s=12a 2t2 solution: a2=2m s2 by the velocity-time relation: 2=a2t=6m s....

3) The velocity of Niuniu's falling h1: 1=a1t=18m s in the buffer process, the circle shouts repentance, and the kinetic energy theorem is obtained by the kinetic energy theorem: w+mgh2....1) The time of Niuniu's whereabouts before being picked up by Seepage Mountain is 3s; (2) When Wu Juping ran downstairs.

1) Because there is a maximum acceleration when the velocity of the skin is zero at the beginning, then the constant force f=ma then vm=p f=p (ma).

2) When the speed is maximum, F amp = constant force f, so bivm = b 2l 2vm (r+r) = ma so b = ......Solve it yourself, it's not easy to fight)

3) That is, the maximum current required, that is, the maximum speed, and the noise is p1=i 2r=(blvm (r+r)) 2 r

4) f--f amp = ma 3 = f --b 2l 2v (r+r) to find the velocity v and then the width of the cover is the same as (3) p2 = i 2r = (blv (r+r)) 2 r

Question 1: (1) Let the dynamic friction factor be , and the acceleration a * g is known for the force analysis of the workpiece, so v a * t1 , that is, , the distance of the workpiece motion in the acceleration process is .

s (v 0)*t1 2 (average speed * time) to get s 2 meters.

2) The remaining distance l s 3 meters is moving at a uniform speed and the time taken is t2 (l s) v seconds, so the whole time is t t1+t2 seconds.

Question 2: There are many ways to solve this problem, and I use the conservation of mechanical energy to do it faster. Because of the large number of known quantities, the results can be expressed in many forms.

m*g*h+m*v0＾2 /2＝m*v＾2 /2

The landing speed is v root number (v0 2 2*g*h).

It can also be done with a flat throwing motion: the final velocity v vertical g*t of the vertical movement is regretted, and the horizontal direction is uniform, so the landing speed is.

v root number [v0 2 (g*t) 2].

Question 3: Be able to understand the meaning of the question. It is known by the title Time Tab TBC t (because XAB XBC).

First, in the vertical Bi Qiang Qin direction: G h t 2 (ybc yab) t 2 to get 10 (5L 3L) t 2, and L 10 cm m into the circle to get T root number seconds.

So the muzzle velocity of a flat toss is v0 xab t 3l t 3* m s

In an electric field, at a certain point, the direction of the force on a positive charge is the direction of the electric field strength of the point, or the tangent direction of the electric field line is the direction of the electric field strength of the point.

The electric potential energy is a scalar convocation thought, has no direction, only a magnitude, and the energy greater than the zero potential point is positive, and the energy smaller than the zero potential point is negative.

The direction in which the positive charge experiences the electric field force at a certain point is the direction of the electric field strength.

The direction and trap of the negative charge at a certain point is opposite to the direction of the electric field strength.

This summary makes no sense.

There are summary points in the library.

When closing the switch k, the pillow shape is the proximal segment of the ball relative to the earth, so the rest of the ball should maintain the same charge, and the pillow itself is not charged, but the charge at one end moves to the other end, and the overall is still electrically neutral, and at this time the earth is far away, so it maintains the same charge as the ball, and there is a negative charge to shift the pillow shape.

The new college entrance examination 3+1+2 physics selection is not chosen, 100 popular science columns, take you to fall in love with high school physics in 3 minutes.

Four scenarios. The direction of the magnetic field is perpendicular to the paper facing inward, and the ions are negatively charged. Pick B. Ant bush.

The direction of the magnetic field is perpendicular to the paper facing outward, and the release yard is negatively charged. Select C.

The direction of the magnetic field is perpendicular to the paper facing inward, and the ions are positively charged. Select C.

The direction of the magnetic field is perpendicular to the paper facing outward, and the ions are positively charged. Pick B.

To sum up, the answer is BC.

According to the Lorentz force, the socks are slowed off, the magnetic inductance line passes through the palm of the hand, the direction of the four fingers, the direction of the four fingers, the direction of the positive ion, the negative ion, the opposite of the negative ion mode, the direction of the big finger is the direction of the force, and then use the compass for a while to be the BC answer.

You can know it by using the left hand.

The direction of the four fingers is the direction of the positive ions, and the negative ions are the opposite, and the direction of the thumb is the direction of the force.

It can be judged. When the ion is a positive ion, the force at point O is in the positive direction of the y-axis, and it can be seen that the pin option C is a negative ion when the attacking wheel is a negative ion, and the force is negative along the y-axis at point O, so it can be known that the answer is B