What is the power 4HP on the motor

HP is the unit of power. The unit characteristics of horsepower are the same as that of watt. They are all the measurement units of power. 1 horsepower is 735.4 watt. 4HP means that the motor is a 4 horsepower motor!

The physical meaning of 60W power of a motor

The motor can do 60 J work per second

The power of a small motor is 2.5W. What is its physical meaning?

Rated output power 2.5W

It's not difficult to find that from 7:00 to 9:00 in the evening, the use of electrical appliances increases, and the lights in the home are darker. After 11:00 in the evening, the use of electrical appliances decreases, and the lights become brighter. Why? Specific reasons
Please do not use too deep language answer, not very understand.

From 7:00 to 9:00 in the evening, more electrical appliances are used, and the lights in the home are dimmer. The reason is that the transmission line is connected in series with the home circuit, and the transmission line has resistance. When the electrical appliances are used more, the current of the main road is very large. According to u = IR, the shared voltage of the transmission line increases, and when the voltage of the home circuit is less than 220 V, the natural light is dimmed
After 11 o'clock at night, the number of electrical appliances used will be reduced, and the lights will become brighter, because the current of the trunk road is smaller, the voltage shared by the transmission line is smaller, and the voltage of the home circuit increases, so the lights will be on
(the voltage transmitted by the power plant is fixed, generally higher than 220 V)

When installing the lighting circuit, in order to check whether the circuit is installed correctly, remove the fuse on the live wire before connecting the power supply, and replace it with an incandescent bulb with a rated voltage of 220 v. at the same time, turn off the switches of all electrical appliances. After connecting the power supply, it is found that the bulb lights normally, so it can be determined that ()
Analysis: it can be judged that the circuit is not installed correctly and there is a short circuit somewhere
The safety device is usually installed under the knife switch and on the live wire. It can automatically cut off the power supply when the current of the home circuit is too high, so as to protect the circuit. The fuse is the internal flow path of the safety device, and there is no current passing through under normal circumstances. If the fuse is replaced with an incandescent bulb with a rated voltage of 220 V, and if the whole household electrical appliances are connected correctly, the safety device can be replaced by an incandescent bulb with a rated voltage of 220 v, When the switch is closed, the lamp should not be on. If the lamp is on, it means that there is a short circuit between the zero line and the live line (there is no electrical appliance between the zero line and the live line), which makes the lamp and the power supply form a closed circuit, indicating that the current in the circuit is too large

Yeah, but we don't usually do that
Generally, use a multimeter to measure the resistance of the zero line and the live line. When all the electrical appliances are not connected, the resistance between the two lines is infinite. If it becomes 0, it means that there is a short circuit

What is the power 4HP on the motor