High School Physics 2 and 3 questions, Senior 2 Physics 3 2 questions .

2 Hovering over the planet indicates that the forces are balanced.

The Coulomb force is equal to the gravitational force.

Going to r 2 means that it has nothing to do with r, so choose b

3. Two charges move in a circle around a certain point in the center, which is a double star model.

The Coulomb force between those two provides the centripetal force because this pair is the reaction force, so the centripetal force is equal, so it is false.

Because of the binary star model, the angular velocity must be equal and correct.

Since the Coulomb force is the action force and the reaction force is equal, v has nothing to do with the amount of electricity error.

2. Levitation shows that gravity is equal to Coulomb force, observing the gravitational force formula and Coulomb force, the two are still equal after doubling the distance.

3, (1) must be wrong, there is only action and reaction between the two, and the force must be equal.

2) Hypothetical method, assuming that the angular velocity is not the same, the two and the line connected to point O cannot be kept as a straight line, and can also appear on the same side of point O, and it is impossible to maintain balance.

3) I think it's right, because the centripetal force is equal, f=m 2r=m v, m is big v is small.

4) The force on particles with high and small power is equal, and the radius of motion is only related to mass.

s=(1/2)at^2

a=2s with argument t t 2=2*8 stupid (2*2)=4m s 2f-mg=ma

m=f (g+a)=42 stove wheel (10+4)=3kg average speed v'=(vo+vt) 2=(0+60) 2=30m sRunning distance s=v't=30*20=600ma=(vt-vo)/t=(60-0)/20=3m/s^2f=

f-f=ma

Traction force f = ma + f = 5000 * 3 + 1000 = 16000n

1. The acceleration of the object is 4m s2

2) The mass of the object is 3kg

2. The distance of the plane is 6000m

The towing force of the aircraft is 16000N

1) Let the direction of the velocity to the right be the positive direction, then the total momentum of the system at the beginning is 3mv0+(-mv0), when the velocity of the wooden block is 0, the total momentum of the system may be 3mv, according to the law of conservation of momentum, there are 3mv0+(-mv0)=3mv, v=(2 3)v0

2) Because the plank is long enough, the bullet will eventually have the same velocity as the block and the plank after being fired, and the whole process uses momentum conservation 2mv0 + (-12mv0) = (3m + m + m) v total, v total = -2v0, and the negative sign represents the direction of motion to the left. And because the ground is smooth, all the energy lost by the system is converted into the internal energy of the wooden blocks and planks, according to the law of conservation of energy.

m+m)l=(1 2)3mv +(1 2)m(12v0) - socks 1 2)(3m+m+m)v, find l

2.Correct answer B

The field strength of the perpendicular line in the middle of the equal charge line is horizontal to the right, first large to small, and the negative charge is repentant, but the electric field force level Chang nucleus is to the left, and the external force level is resistant to the front and digging to the right. The size is from large to small.

3. .Correct answer c

The force is to the left, the acceleration decreases, and the field strength decreases.

2.Solution: obtained from Newton's second law f=ma:

m=f1/a1=4/2=2kg

f2=ma2=2×6=12n

3.Solution: obtained from Newton's second law f=ma:

M A = F A A = F

M B = f A B = f

m A M B = (2f 3) (2f 9) = 3 times.

It's better to send a reply to planning regulations and send a reply to a reply.

It's not from high school, it's a three-phase circuit, and if you teach this in high school, worship.