Physics 2 Fast Physics 2 Physics Puzzles

1.Use the spring dynamometer to pull a wooden block on a smooth horizontal plane to do a uniform linear motion, and write down the spring dynamometer indicator f1

2.Pull a wooden block on the rough ground with a spring dynamometer, find that the wooden block does not move, and write down the indicator f2 of the spring dynamometer

3.According to the principle of two-force equilibrium, F1 is the sliding friction and F2 is the static friction, comparing F1 and F2, it is found that F1 is smaller than F2, that is, the static friction is greater than the sliding friction.

It doesn't have to be like this, it's pretty much the same.

Hold an object with a thread. For example, wooden blocks. On rough ground.

Pull the rope. You will find that you can't pull at first. When pulled, the block will suddenly move forward.

The acceleration is very high. Then move forward at a uniform pace (as long as you have the ability to control your strength)...That's not all there is to it.

Make a ramp and put it on the tabletop, a trolley mass m1 and a fast wood mass m2, they are respectively lowered from the top of the slope to the bottom of the slope, and slide along the table for a distance. The time of the two movements on the slope was measured t1 and t2, respectively, and the time of movement on the table was t1 and t2, and the length of the two slides out on the table was measured to be s1 and s2

On an inclined plane, an object moves by gravity and friction. In this way, you can calculate the friction between the two, compare them, and you can confirm your thoughts.

Upstairs, you can see the magnitude of the force by pulling it with a spring dynamometer, which is more intuitive and convincing.

The compressor sometimes works and sometimes rests during the day. It only consumes power and does work when it works, so according to p=w t, w=, there is no problem with this calculation, and t is less than, and far less than 24h, so the calculation of power p is small.

The true power should be calculated by dividing the W by the operating time of the compressor. Because the refrigeration effect of each refrigerator is not the same, it is not easy to calculate. You can use another formula for calculating the power of electricity, p=ui, (u is the voltage, i is the current, these two data can be found from the nameplate or description in the refrigerator) to calculate the power of the refrigerator.

Hope it works for you!

The refrigerator does not work 24 hours a day, there are intermittent ones, and it will stop working when the temperature is lower than the set temperature, and start working again when the temperature rises to the corresponding temperature.

1) b Using the control variable method, the speed of the knowledge block is changed, and the experiment proves that the friction force is independent of the velocity.

2) The constant velocity is that the net force experienced by the wooden block is zero, and the tensile force experienced by the oak block is equal to the sliding friction force, that is, the indication of the spring dynamometer is equal to the frictional force experienced by the wooden block.

3) C method is: first put the wooden block flat on the wooden board, pull it horizontally at a uniform speed with a spring dynamometer, record the spring dynamometer indication, and then put the wooden block on its side, or pull it horizontally at a uniform speed, record the spring dynamometer indicator, compare the two indications and find that the friction force has nothing to do with the contact area.

1) b2) The force on the wooden block when pulling at a constant speed is the balance force, and the indication of the spring dynamometer is equal to the friction force.

3) C change the way the wooden block is placed (flat, sideways, and vertically placed), pull the wooden block at the same speed and at a constant speed, and observe the number of the spring dynamometer to know the number of f1, f2, f3, and compare the size of the three

1. B2, when the animal block is pulled at a constant speed, the object is in a state of equilibrium, the two forces in the horizontal direction are balanced, the Lana hail force is equal to the friction force, and the number of views and friction force of the spring dynamometer are equal.

3, C1), the cuboid wooden blocks are placed flat, sideways on the board, with a spring dynamometer to pull the object horizontally and at a constant speed, and the hole is written down twice The tensile force F1, F2, 2), compare the size of F1 and F2, and obtain whether the size of the friction force is related to the contact area.

It is related to the size of the contact area between objects.

One. If the height of the liquid level is equal, because the ice floats, the weight of the water discharged is the same as the weight of the ice, then after the ice melts into water, the weight of the water is the same as the weight of the ice, then after the ice melts into water, the weight of the water is also the same as the weight of the water discharged before melting, so the volume of the two times is the same, two.

Falling, first of all, you have to know that you compare the volume of water discharged each time which is larger, which is bigger, which time the liquid level is higher, so as to judge the rise and fall of the liquid level, the two boats are floating has no effect on the liquid level, the stone is floating for the first time, the weight of the water is equal to the weight of the stone, the second time it sinks, the weight of the water is less than the weight of the stone, then the water weight of the first time it is discharged, and thus the volume of the discharge is large, so the first time the liquid level is high, the second time it is low, so the liquid level drops.

In fact, it can be expressed in expressions, but the letters are too inconvenient, so they are described in words, I hope you can understand, the point is to know what the two comparisons are, the two questions seem to be similar, but the amount of comparison is different, there is something I don't understand is asking me, I am a physics teacher.

Solution: It can be seen that voltmeter V1 measures the voltage of L2.

Voltmeter V2 measures the voltage of the power supply.

So the reading of v1 is:

Because the supply voltage U1+U2

So V2 Note: V2 is quite open there, and the circuit is actually L1 and L2 in series.

v1 Reading:

v2 Reading: This circuit is a simple series circuit

1. The idiom can immediately explain that the optical law is that light travels in a straight line

2. As the saying goes, the moon in the water is empty, which means that the January in the water is the virtual image of the moon in the sky in the water

1. There is a device that can reflect the water vapor content in the air, called the dry and wet thermometer, which is made up of two identical thermometers in parallel, one of them is wrapped in a wet cloth, and the readings of the two thermometers are different, and the reading of the wet bubble thermometer is lower than (low), which is due to the fact that the water in the wet cloth is endothermic at a certain temperature, and the difference between the readings of the two thermometers is small at a certain temperature. Indicates that the humidity of the air is higher (greater) 2 The temperature of the water in the fish tank at home is generally lower than the indoor air temperature, which is caused by the water (evaporative heat absorption).

3. The exterior of the Shenzhou spacecraft is coated with a special material, which is first (melted) and then (vaporized) at high temperatures

4. After taking out a thermometer from the alcohol, what is the change in the thermometer's indication first, first decreases and then increases.

5. There is an air conditioner in the car, the cab is warm in winter and cool in summer, but when using the air conditioner, it will cause the front glass to blur and affect the line of sight.

6. Drip water into a boiling oil pan and the oil will splash everywhere What is the reason for this.

The oil temperature is very high, and the water absorbs heat and vaporizes violently after dripping into the water, so the oil will splash around.

1 large evaporation low.

2. Evaporation and endothermy.

3. Melting and vaporization.

First down and then up.

5AC6 water is denser than oil, water is below, oil is on top, water boils, bursts bubbles, splashes the oil.

1. Agree with the statement upstairs: use an alcohol lamp to heat the wick, and at the same time observe the indication of the ammeter.

2. (1) As shown in the figure, I re-drew it according to your drawing, here you can clearly see that the left end of the voltmeter is directly connected to the positive pole of the power supply, and the right end is connected to the negative pole of the power supply through the ammeter 2, because the ammeter can be regarded as a wire, so the indication of the voltmeter is the voltage of the power supply, and the same is true that the ammeter can be regarded as a wire, so it is equivalent to the lamp L1 and the lamp L2 are connected in parallel at both ends of the power supply, so the voltage at both ends of his imitation is the indication of the voltmeter.

2) The ammeter A2 measures the current of L1; The ammeter A1 measures the total current of L1 and L2, so the current of L2 is the number of A1 minus the number of A2.

1 Heat the wick with an alcohol lamp and analyze the ammeter while observing the number of the ammeter to draw conclusions.

Tulingbi is the power supply plus switch, the state Wang ridge plus the lamp book, the bubble plus the ammeter.