Unit Conversions Grams to Watts

• MD_Programmer
In summary, the power available can be calculated using the equation Pout = Tc * v, where Pout is in watts, Tc is in grams, and v is in m/s. In order to determine efficiency, the units must be properly converted. Conversions provided are: 1 gram = 0.002205 lbs, 1 m/s = 3.28 ft/s, 1 horsepower = 550 lb*ft/sec, and 1 horsepower = 745.7 watts. After converting the units, the calculated power available may be very small, indicating a very low efficiency.
MD_Programmer

Homework Statement

The power available (output) is measured by the velocity at which you are moving and the thrust
required to create that movement. NOTE: Conversions for proper units are provided below
equation.

Power Available: Pout = Tc * v

where: Pout = power available (watts)
Tc = Calibrated thrust (grams)
v = wind tunnel velocity (m/s)

In order to determine the efficiency, the units must cancel. To convert the units so that the output
power is in watts, use the following information:

can't get the power right help?

Homework Equations

1 gram = 0.002205 lbs.
1 m/s = 3.28 ft/s
1 horsepower = 550 lb*ft/sec
1 horsepower = 745.7 watts

v = 3 m/s
Tc = 0.0040 g

The Attempt at a Solution

(0.0040*0.002205) = 8.82 E-6

(3*3.28) = 9.84 ft/s

((8.82 E-6 * 9.84) *550) / 745.7 = 6.401212284 E-5 watts

Last edited:
I think you're right in everything except going from lb*ft/sec to watts. Check your unit conversions. I think you should divide by 550 and then multiply by 745.7.

I got 0.000 watts using that method but that doesn't sound right because my efficiency calculations after are barely 1% and this data should keep to where they don't get above 80% according to the professor

MD_Programmer said:
I got 0.000 watts using that method but that doesn't sound right because my efficiency calculations after are barely 1% and this data should keep to where they don't get above 80% according to the professor

These are extremely small magnitudes you are dealing with, so you should be using scientific notation in your calculations.

You haven't provided any efficiency calculations, so it is not clear what your problem is.

It's hard to envision what sort of mechanism you are dealing with (a gnat on afterburners, perhaps), but whatever it is, only microscopic amounts of power are being generated.

To convert grams to watts, we need to use the following conversions:
1 gram = 0.002205 lbs
1 m/s = 3.28 ft/s
1 horsepower = 550 lb*ft/sec
1 horsepower = 745.7 watts

We are given that the calibrated thrust is 0.0040 grams and the wind tunnel velocity is 3 m/s. Therefore, we can calculate the power available (Pout) using the equation Pout = Tc * v.

Pout = (0.0040 * 0.002205 * 3 * 3.28 * 550) / 745.7 = 0.006 watts

Therefore, the power available is 0.006 watts. This means that for every 0.006 watts of power available, we need to use 0.0040 grams of calibrated thrust and have a wind tunnel velocity of 3 m/s.

1. How do I convert grams to watts?

To convert grams to watts, you will need to know the density of the substance in grams per cubic centimeter (g/cm3) and the specific heat capacity in joules per gram per degree Celsius (J/g°C). The formula for this conversion is: Watts = (grams x g/cm3) x (change in temperature in °C x J/g°C).

2. Can I convert any substance from grams to watts?

Yes, you can convert any substance from grams to watts as long as you have the necessary information for the formula mentioned above. However, keep in mind that this conversion is specific to the substance's density and specific heat capacity, so the results may vary for different substances.

3. How do I know if my conversion from grams to watts is correct?

You can check the accuracy of your conversion by using an online conversion tool or by comparing your results to a known conversion for the same substance. It is also important to double-check your calculations and make sure all units are consistent throughout the formula.

4. Why do we need to convert from grams to watts?

Converting from grams to watts is useful in various scientific fields, such as chemistry and physics. It allows us to quantify the amount of energy needed or produced by a certain mass of a substance. This can be helpful in experiments and real-life applications, such as determining the energy efficiency of a substance.

5. Is there a shortcut or easier way to convert from grams to watts?

Unfortunately, there is no shortcut or easier way to convert from grams to watts. The formula mentioned above is the most accurate and reliable method for this conversion. However, you can use online calculators or conversion charts to make the process easier and faster.

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