Urgent!!! Physics. A problem solving process is required.

Suppose A is solid and the volume is VA.

Because the masses are equal, then v A A = (v B - v) B, and because A: B = 4:1, v A: v B = 1:5, i.e. A = 4 B, v B = 5 v A.

Thus there is v A4 B = (5v A-v) B.

The solution gives v A = v, assuming that B is solid and the volume is v B.

Since the masses are equal, then (v A-v) A = v B B, and because A: B = 4:1, v A: v B = 1:5, i.e. A = 4 B, v A = B.

Thus there is (B-v) 4 B = v B B.

The solution shows that v B ==-20v cannot be negative, so it is assumed that the solid sphere is A and the volume is v if it is not established

The first solid one.

v A: v B = 1:5

v B - v A = 4

v = 4 v A = 1

v A = 1 4 V

Solution: Because v A: v B = 1:5, the ratio of density A : B = 4:1, so m A: m B = 4:5, but the masses of A and B are equal, so B is hollow.

Because the volume of the hollow part of B is v, the total volume of B is 5v, so the volume of the solid sphere is v

If they are all solid, they are composed of p A*v A=p B*v B, and 1*4<5*1Therefore B is known to be hollow.

Solve the equation pA*vA=pB*(vB-v), and then obtain the ratio of density A:B=4:1 by vA:vB=1:5.

v A = v

(1) The weight of the water stored in the upper reservoir m = density * volume =

From the title, it can be seen that the gravitational potential energy of the water in the upper reservoir is converted into electrical energy.

That is, there is mgh*75%=p

Then we can see that we can generate electricity p= per day

2) If 1 year is calculated as 365 days, then the electricity generated is p1 = kWh.

t=2 丌*根号(l g).

t1 = 2 丌 * root number (l g1).

t1 t = root number (g g1) = root number {(gm r 2) [gm ((r+h) 2]=(r+h) r

h=rt1 t -r=r[(t1 t)-1]r -- radius of the earth.

Sea level: t=2 root number (l g).

A certain height: t1=2 root number (l g1).

It is obtained: g1=t*t*g (t1*t1).

Sea level: g = (gm) (r 2).

A certain height: g1=(gm) (r1 2).

r is the radius of the earth).

Yields: r1=t1*r t

h=(r1-r)=(t1-t)r/t

Because the object moves horizontally at a constant speed, it is subjected to an equilibrium force. The tensile force f is equal to the frictional force 5n, the distance of horizontal movement is 5m, and the work done by the tensile force f is w=fs=5n*5m=25j

Because it is a uniform motion, the tensile force = friction force = 5n, w = f * s = 5 * 5 = 25j

p=iu

Current i = 10000 250 A

250-220=ir

Line resistance r=

The percentage of power lost on the transmission wire as a percentage of the total power (i2 r) 10000=

First from the front 10 kilowatts 250 volts to know that the wire current is 40 amps, and then get the 220 volt voltage to know that the loss is 30 volts, so the resistance is 300 watts, and then the loss is 300 watts, the resistance is, so the coil current is 20 amps, according to the current ratio and the coil is inversely proportional to the original subcoil ratio is 1:2, the figure is very simple, have you learned? No, you can ask me again (

Tell you a conclusion that when an object is in the interior of the planet, its gravitational acceleration is proportional to its distance to the center of the sphere, that is, r r=g' g, where r is its distance from the center of the sphere, r is the radius of the planet, g' is the gravitational acceleration at the point, g is the gravitational acceleration on the surface, as for how to deduce this conclusion is more complicated, to remove the mass of the planet above the point, understand it as its surface of a new planet.

According to this, d=r(1-g2 g1).

Centripetal force MV 2 = Coulomb force Fe + pipe wall support force fn - gravity mg because fn is the reaction force of the ball to the pressure of the pipe wall.

Therefore mv 2=fe=qe

fe 丄v, fe does not do spike work, and the ball is conserved from a to b mechanical energy.

mgr=(1/2)mv^2

mv^2=2mgr=qe

e=2mgr/q

The time elapsed by 10 meters to hear the gunshots is 5 340

So when the gunfire is heard, the bullet advances 680*5 340=10 meters.

The time when a person hears the sound is: t = 5 340s, and the distance traveled by the bullet is: s = vt = 680 * (5 340) = 10m

(1) p=f s can know that the pressure of water in the container on the bottom of the container is p=12

2) After the object is put into the water, if the liquid level is not out of the container, the water rises to a height of 2 10 -4, and there is a change of p= water gh=1 10 10 2 10 -3 = 20pa

After the object is placed in water, if the liquid level itself is level with the wall of the device, the height of the liquid level will remain unchanged, and the water overflows, so the pressure will not change, that is, the change is 0, that is, the range is between 0 and 20pa.

The first question is just a formula, and the second question is just the gravity of the water that is discharged.

I think you should read the book.

Is the water drained by the block overflowing?

1. 12÷

2.The height of the liquid level is raised = 2 * 10 -4 p = density * g * h = 1 * 10 3 * 10 * 2 * 10 -3 = 20 pa but it is possible that the water is full before the block is placed, so: the range is between 0-20pa.