The following processes are examples of work that are used to change the internal energy of an objec

The answer is that both b and b change the internal energy of the object through friction.

c is the change in the internal energy of an object by heating.

That's right. There are two ways to change the internal energy of an object: work done and heat transfer, and in changing the internal energy of an object, work done and heat transfer are equivalent

1. Heat transfer.

Whenever there is a temperature difference between objects or between different parts of the same object, heat transfer occurs until the temperature becomes the same The essence of heat transfer is the transfer of internal energy from a hot object to a low temperature object, or from the high temperature part of the object to the low temperature part.

2. Do work. If the outside does work on the object, then the internal energy of the object will increase, and if the object does work on the outside world, the internal energy of the object will decrease. The essence of the work done to change the internal energy of an object is the process of mutual transformation between other forms of energy and internal energy.

The common ways to change the internal energy of an object by doing work are mainly as follows:

1. Compress the volume, and increase the energy in the object For example: pump pumping.

2. Friction generates heat, and the energy in the object increases, for example: drilling wood for fire.

3. Forging objects, the energy in the object increases, for example: hammer striking iron.

4. Bend the object, and the energy in the object will increase For example: repeatedly bending the wire.

5. Gas expansion does work, and the internal energy of the object decreases For example: steam engine.

That's right. The work done on the friction of an object is the conversion of mechanical energy into internal energy.

Work is done on gas compression.

The electric current is converted into internal energy by doing work through the heating wire to make it heat.

Work is a measure of the transformation of energy.

Answer B analysis: To solve this kind of question, you should know that there are two ways to change the internal energy of an object: work and heat transfer, the heat transfer process is the transfer process of energy, and the work process is the transformation process of energy

Answer: a. After the ice cube is put into the juice, the heat will be transferred from the juice to the ice cube, so that the internal energy of the juice will be reduced, and the temperature will be reduced, so it will feel cool when drinking, and the internal energy of the juice is changed through heat transfer, which does not meet the topic;

b. The mechanical energy is transformed into the internal energy of the hand, and the internal energy of the hand increases and the temperature rises, which changes the internal energy of the object through the work, which is in line with the topic;

c. Putting a pot of cold water on the stove fire to heat the water temperature is the internal energy of the object changed by heat transfer, which does not conform to the topic;

d. Put a cup of boiling water on the table, and the gradual decrease in water temperature is the internal energy of the object changed by heat transfer, which does not meet the topic;

Therefore choose b to pay homage.

Comments: Although both work and heat transfer can change the internal energy of an object, heat transfer is the transfer of internal energy, while work is the transformation of internal energy and mechanical energy, and the essence of the two is different

Answer C Analysis: When boiling water on the stove, the temperature in the furnace is higher than the temperature of the water, and the heat is transferred from the stove to the water, which is the internal energy changed by the overheating transfer of the dust; When there is a fever, the temperature of the person's forehead is higher than the temperature of the cold towel, and the heat is transferred from the forehead to the cold towel, which changes the internal energy of the object through heat transfer; Use the cylinder to pump the tire, the piston and the cylinder wall friction to do work, the mechanical energy into internal energy, so that the energy in the cylinder wall increases, the temperature rises and heats, so this is through the way of work to change the internal energy of the object; In the hot summer, the temperature of the sun is higher than that of the asphalt road, and the heat is transferred from the sun to the asphalt road, so that the internal energy of the asphalt road increases, and the temperature rises, so this is through the way of heat transfer to increase the internal energy of the asphalt road

Comments: This question examines two ways to change the internal energy of an object The main way to distinguish between the two ways is to see if the form of energy has changed during the change of the internal energy of the object

Answer A analysis: There are two ways to change the internal energy of an object: work and heat transfer, the heat transfer process is the transfer process of energy, and the work process is the transformation process of energy

Answer: a. When sawing wood, the saw rubs against the wood, and the friction generates heat, which uses work to change the internal energy of the object, which is in line with the topic;

b. The transfer of solar energy to people when basking in the sun is to change the internal energy of the object through the heat transfer method, which does not conform to the topic;

c. Alcohol is easy to evaporate, and it will absorb heat from the body when it evaporates, so it will feel cooler than other places, which is not in line with the topic;

d. The red-hot iron releases heat and the temperature decreases, which is the change of the internal energy of the object through the heat transfer method, which does not conform to the topic.

Therefore, choose a Comment: This question examines the identification of the internal energy of the object changed by work and heat transfer, which is closely related to the reality of life, and belongs to the common question type of the high school entrance examination

Answer B Test point: Do work to change the internal energy of the object

Analysis: There are two ways to change the internal energy of an object, one is to do work, and the other is heat transfer The difference between the two methods is that there is no transformation of energy in the process of heat transfer, but the transfer of simple energy such as osmosis The work process is the transformation of energy, which is the process of converting other forms of energy into internal energy

Answer: Solution: a. The use of gas stove to boil water is the process of transferring the heat generated by gas combustion to water, which belongs to the use of heat transfer to change the internal energy of water

B. After the car travels a certain distance, the tires will heat up, consume mechanical energy, and get internal energy, which belongs to changing the internal energy of the object in the form of work in line with the topic

c. The water in the solar tank is heated, and the water absorbs the radiant heat of the sun to increase its internal energy, which is a form of heat transfer that does not meet the topic

d. Ice cubes are put into the juice, the temperature of the ice cubes is low, and the juice with high temperature slag has a heat transfer, and the juice transfers heat to the ice cubes, which belongs to the conversion of energy and does not meet the topic

Therefore, choose B Comment: The key to distinguishing between work and heat transfer is to see whether it is the transformation of energy or the transfer of energy

Answer B put ice cubes in the freshly squeezed juice before the stall, and when you drink it, you feel that Kai Qingye is very cool, and it reduces internal energy through heat transfer, A is wrong.

When the hands rub against each other, they will feel hot, and the internal energy will be increased by doing work, b right. Putting a pot of cold water on the stove fire to heat the water temperature and heat the heat transfer to increase the contents, c wrong. Put a cup of boiling water on the table, the temperature of the water gradually decreases, and the heat transfer reduces the internal energy.

Answer] C Answer Analysis] Test question analysis: a. The warming of the room belongs to the internal energy of the object changed by heat transfer, which does not meet the difference in the question;

b. Boil water in a stove and the temperature of the water rises.

It belongs to the heat transfer to change the internal energy of the object, which does not conform to the meaning of the ruler;

c. Using the method of beating to make the steel plate hot, the essence is to do work to change the internal energy of the object, which is in line with the topic;

d. The suction stroke of the gasoline engine is completed by inertia, and there is no force to do work, which does not conform to the topic;

Test point: The way in which the internal energy of an object is changed.

Comments: This question examines the two methods of changing the internal energy of an object: work and heat transfer To judge the phenomenon of selling the skin to do work to change the internal energy of an object, it is necessary to know the characteristics of work

Answer] A Answer Analysis] Question Analysis: There are two ways to change the internal energy of an object: work done and heat transfer.

The two hands rub against each other, and the increase in the temperature of the palm is to overcome the friction to do work, increase the internal energy of the hand, option A is in line with the topic, optional A; When you have a fever, use a cold towel to cool your head, put vegetables in the refrigerator, the temperature of vegetables is low, and under the sun, the temperature of the stone benches in the park rises to the contact of high and low temperature objects, and the high temperature objects are heat-absorbed, and the internal energy of high-temperature objects is transferred to low-temperature objects through heat transfer, and the b, c, and d options do not meet the topic.

Test point: Distinguish between two ways to change the internal energy of an object.