Help me look at this physics problem Thank you

B The thermometer has been damaged.

B thermometer in the open of the alcohol, due to the volatilization of alcohol, so B has a lower indication-number than A, due to heat transfer, the temperature in the closed bottle and the air temperature are the same. So A and C are the same temperature.

So B is broken.

Because the small amount of alcohol in the closed bottle should be the same temperature as the air in the same space, and the alcohol in the open glass should be low because it has to volatilize and take away the heat!!

And they all show the same temperature, that said the name B is broken!!

It should be that the B thermometer has been damaged, because the alcohol evaporation on its surface is endothermic, so the indication should be less than 20 degrees.

The answer should be C. It should be in a steady state, the air temperature should be the same, the temperature measured at the mouth of the bottle is the same as the air measured, and it feels really cool with your hands, but the temperature is the same definition.

Just like an ice-water mixture, put enough ice cubes in boiling water to ensure that it becomes an ice-water mixture, just like if you put enough ice cubes in cold water to make an ice-water mixture, the temperature is the same as 0 at normal pressure

C is a closed container, in the case of 20 degrees, due to the volatilization and vaporization of alcohol, the pressure inside will change (become larger), at this time there will be a gap between the internal temperature and the outside, it should be slightly lower!!

B is damaged because the alcohol on its surface evaporates to be endothermic.

C, 100% correct, there are too many details, you add another 50 points and I will make it clear to you.

(1) The vibration equation is x=acos(t+).

So the amplitude a=

Angular frequency = 20Hz

Cycle = 2 20

The initial phase = 2) t = 2s is obtained by the formula.

Displacement x = velocity v = -a sin( t+ )2 sin( 4) = acceleration = f m =

There is no m value, and there is no indication of what type of simple harmonic vibration it is, so it is not calculated.

B in A is perpendicular to the surface of the paper, while V is on the plane of the paper, and the plane where V is located is perpendicular to B. In fact, as long as b, l, and v are at a 90° angle to each other, it is a three-dimensional scale calculation, so b is undoubtedly the correct answer.

You are wrong, the angle in A is the angle with the horizontal plane, not the angle with L or the magnetic field, it must be the angle with L or the direction of the magnetic field to multiply the angle.

In Figure A, the direction of the magnetic field is perpendicular to the inward surface of the paper, and the direction of the conductor cutting is parallel to the paper surface, so the conductor is perpendicular to the magnetic inductance line, of course, it is calculated with e=blv. The angle in the diagram is only the angle between the direction of movement of the conductor and the horizontal direction.

One. 1.Obviously, the volume of water is the volume of the bottle, so it will not change after the modification of alcohol, and it is the same cubic meter;

2.The mass does not change, so (water)v(water) = (ice)v(ice), so, v(ice) = (water)v(water) (ice).

1000*cubic meters, so, the increased volume is v=v(ice)-v(water)=4 45 cubic meters = cubic meters.

Two. Because the metal is completely immersed in both alcohol and water, the volume of the liquid that spills is equal, i.e. m (wine) (wine) = m (water) (water), therefore, m (water) = m (wine) * water (wine) = 16 * 1 g = 20 g.

Only c. Analyse.

a。It can be calculated according to the formula of gravitation, which is obviously not true, and should be a formula related to the square of distance.

b。After the jet, the speed changes, the orbit also changes, and it is no longer a circular track, so it will not catch up.

c。Correct, according to the law of circular motion and the law of gravitation, the formula is easy to get.

d。The mass of the satellite is not known, and the mechanical energy cannot be determined.

A should be GR2R2

b acceleration changes orbit.

c should be: [(3+2k) r]* r 3 g)d The two satellites have the same mass, the same orbit, the same velocity field, and therefore the same mechanical energy.