Heat 2 iron balls of the same volume and mass at the same time

Let's start by saying that your answer is wrong.

It is the temperature of the suspended ball that rises quickly.

The thermal expansion of the object, the cold contraction, the heating for the same time, then the energy is the same for them, and the hanging ball decreases due to the enlargement of the center of gravity and the downward shift of the center of gravity.

The ball placed on the table rises in the center and the gravitational potential energy increases and it has to take out a part of the heat to convert into gravitational potential energy.

Therefore, the temperature of the suspended ball rises high.

In the end, the answer seems to be because the center of gravity hanging in the air has shifted downward, and the center of gravity placed on the table has shifted up, so the temperature on the table has risen faster.

And the reason for this is that the volume increases, the center of gravity in the air moves down, the center of gravity on the table moves up.

And by the conservation of energy, so the temperature on the table rises quickly.

Rational point, always remember the conservation of energy, since it is two identical things, to see if the input and output of energy are the same, the question itself is not comprehensive, if the table is made of wood or plastic, it must be fast on the table, but if the table is iron, it is fast in the air, the specific heat capacity is not the same, the heat loss is not the same!

The rise and fall of the center of gravity is caused by thermal expansion and contraction, and the ball on the table consumes energy because of the rise of the center of gravity, so this factor will have a cooling effect on him.

The center of gravity that hangs in the air moves down, and the center of gravity that rests on the table moves up?

The convection of air around the iron ball placed on the table will be limited to a certain extent, so its own heat will be slowly dissipated;

The iron ball hanging in the air, the air around it is free convection, the hot air rises, the surrounding air will come to replenish, and his heat is dissipated quickly.

Regardless of heat loss, the center of gravity of the iron ball placed on the table shifts upward, and the gravitational potential energy increases, and part of the heat absorbed by the iron ball is converted into increased potential energy. While the iron ball hanging in the air, the gravitational potential energy decreases, and part of the gravitational potential energy is converted into the internal energy of the iron ball. Therefore, the temperature of the iron ball on the table rises slowly, and the temperature of the iron ball in the air rises quickly.

What does this have to do with the center of gravity? It should be related to heat loss.

Two identical balls with the same temperature increase means that their internal energy increases by the same amount Because they are heated and expanded, the rope does not elongate, so the center of gravity of ball A decreases, and the table does not expand thermally, so the center of gravity of ball B increases, which means that ball B increases in addition to the same internal energy as ball A, and also increases mechanical energy, that is, potential energy, It can be seen from the energy conversion and conservation of energy that ball B absorbs more heat.

Because the round socks are good for the public stove in the public stove:

Therefore, the volume of two iron balls and the hidden mountain is 4 3 (4+2) 3 = 4 3 * 216 = 288 cubic centimeters, and the volume of the fused iron balls is 288.

Radius of the fused ball: r=216 (1 3).

Surface area of the fused spheroid: s = 4 r

Because the round socks are good for the public stove in the public stove:

Therefore, the volume of two iron balls and the hidden mountain is 4 3 (4+2) 3 = 4 3 * 216 = 288 cubic centimeters, and the volume of the fused iron balls is 288.

Radius of the fused ball: r=216 (1 3).

Surface area of the fused spheroid: s = 4 r

m1ρv1

kg/m3t1j（kg?℃）

Answer: The amount of heat to be absorbed is a good ruler; m2q

c△t65j

j(kg?℃)35℃?30 Judgment Lu).

The socks are hollow

Q absorbs m water c water (t water end t beginning).

Q put m iron c iron (t early late open dismantle t iron end).

It is known that q is put q at the beginning of t t iron powder t water powder x

m water c water (t end yard jujube x) = m iron c iron (x t beginning) degrees Celsius) * (x - 20 degrees Celsius) * (71 early potatoes x degrees Celsius) 420x-8400 = 16330-230x

650x=24730x=

C iron m iron (T-61) = C water m water (61-15).

t = 46 c water m water c iron m iron + 61 = 46*

Q suction = cmδt = q discharge.

C iron = c water =

Bring in the formula. x=481℃

(1) Known: v=100cm3, m=, iron.

kg/m3=

If the ball is solid, according to =m

v can be obtained its volume should be: v iron. =m

Iron. =390g

50 cm3 because of V iron.

v, so this ball is hollow, and the volume of the hollow part:

v empty. = v-v iron.

100cm3

50cm350cm3

2) If the hollow part is filled with water, the mass of the water, m water.

Water. v empty. 50cm3

50g, the total mass of the iron ball after filling with water:

m total. = m water.

m=50g+390g=440g．

Answer: (1) The ball is hollow;

2) If the hollow part is filled with water, the total mass of the ball is 440g

q=cm△t

q – Absorbed (released) heat.

c - specific heat capacity.

m – the mass of the object.

t - the temperature difference between the front and back.

From the formula, it can be seen that the same mass of iron ball and copper ball, the temperature difference is the same, so the heat absorption (release) is more than the heat capacity, if you do not use the formula, the properties of each substance are different, the properties of iron and copper are also different, the heat absorption capacity is the same as the density, the hardness is the same, she is only related to the type of substance (not involving temperature), so the heat absorption capacity is also different, take an example, the same mass of water and iron, starting from the same temperature, after a period of time, it must be the iron cool!

Since they have the same mass, the same initial temperature, and the time they have been in the water for a long enough time, the final temperature of the water is the same, so the final temperature of the copper ball and the iron ball are also the same, but because their specific heat capacity is different, it can be judged that the heat absorbed is different according to the formula q=cm(t2-t1).

You think of it this way: heat absorbed = specific heat * mass * amount of temperature change. Although the mass and temperature change are the same, the specific heat capacity is different, so the amount of heat absorbed is of course different.

What does not change: mass and specific heat capacity. The volume becomes larger, and the density decreases.

The density of a substance changes under the influence of temperature. In general, the mass of a substance is not affected by temperature (it is very small), but the volume expands and contracts in a thermal manner. Therefore, when the temperature rises, the volume expands (except for water), and the density becomes relatively smaller.

The mass specific heat does not change, the volume is large and the density becomes smaller.

What does not change is the mass specific heat capacity, what becomes larger is the volume, and what becomes smaller is the density.