Interpreting J/s and J/(s^2): Watts & More

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In summary, J/(s^2) is a unit used to measure the rate of change of power, particularly in cases where power is not changing at a constant rate. This unit can be useful in practical applications, such as calculating the power transmission in a car's power shaft, where rotational acceleration is taken into account.
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TSN79
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Just trying to interpret some units here. If J/s is Watt, what does J/(s^2) tell me?
 
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W/s is the rate at which power increases. I can't think of an example of where this unit might be commonly used.

Claude.
 
  • #3
Something's power is increasing by 1 J/s every second.
 
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It is the rate at which power is used, as other have said before me. A practical example, you have a power transmission shaft of a car with an applied torque T, with a constant rotational speed, n. You want to determine the power transmitted to the shaft. Then you will have
[tex] \dot{W_{sh}} = 2 \pi \dot{n} T [/tex]

Edit: Oh, I see you said watts/second. Forget what I said above. That would be the rate of the rate at which power is being used. Well, you could change my n dot to an n double dot, where the n double dot is the rotational acceleration I guess. But I can't see any purpose for doing so. I guess you could interpret it as the rate at which the power being transmitted through the shaft is changing with respect to time, if it has a nonuniform speed, n. If you know n double dot, you can integrate to find the power transmission from [tex] t_0 [/tex] to [tex] t_1 [/tex]

[tex] \dot{W_{sh}} = \int^{t_1}_{t_0} \ddot{W_{sh}} dt = \int^{t_1}_{t_0}2 \pi \ddot{n} T dt [/tex]
 
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1. What is the difference between J/s and J/(s^2)?

The main difference between J/s and J/(s^2) is that J/s measures power (watts) while J/(s^2) measures power per unit of time (watts/second). J/s is a measure of the rate at which energy is transferred, while J/(s^2) is a measure of the rate at which power is changing.

2. How are J/s and J/(s^2) related to watts?

J/s and J/(s^2) are both related to watts. J/s is equivalent to one watt, as they both measure power. J/(s^2) is equivalent to one watt per second, which is a measure of the change in power over time.

3. How can J/s and J/(s^2) be used in scientific research?

J/s and J/(s^2) are important measurements in many scientific fields, including physics, engineering, and chemistry. They are used to describe the transfer and change of energy and power, which is crucial in understanding various natural phenomena and designing experiments.

4. What are some common examples of J/s and J/(s^2) in everyday life?

Examples of J/s in everyday life include the power output of a light bulb, the rate at which a car's engine produces energy, and the rate at which a person burns calories while exercising. J/(s^2) can be seen in the acceleration of an object, the rate at which a battery loses charge, and the power output of a sound wave.

5. Can J/s and J/(s^2) be converted to other units?

Yes, J/s and J/(s^2) can be converted to other units. J/s can be converted to watts, kilowatts, or megawatts, depending on the magnitude of energy being transferred. J/(s^2) can be converted to watts/second, kilowatts/second, or megawatts/second, depending on the rate of change in power. These conversions are important in understanding and comparing different energy and power measurements.

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