Can You Convert Watt-Hours to Watts in Energy Calculations?

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Homework Help Overview

The discussion revolves around converting watt-hours to watts in the context of an automobile's fuel efficiency and energy consumption. The problem involves understanding the relationship between energy and power, specifically in terms of gasoline consumption and its energy content.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the compatibility of watt-hours and watts, questioning how to convert energy into power. There is an emphasis on understanding energy consumption over time and the definitions of energy and power.

Discussion Status

Some participants have offered clarifications regarding the definitions of energy and power, noting that the conversion from watt-hours to watts is not straightforward. There is a focus on calculating energy consumption per time unit, but no consensus has been reached on a specific method to approach the problem.

Contextual Notes

The original poster's attempt at a solution indicates confusion about the conversion process, and there is mention of the energy content of gasoline as a key factor in the calculations. The discussion reflects a need for further exploration of how fuel consumption relates to energy usage over time.

tacojohn
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Homework Statement



An automobile gets 20 miles per gallon when traveling at 60 miles per hour. With the energy content of gasoline at 36,000 watt-hr per gallon, convert this amount of power into watts.

Homework Equations



W h (watt hours) | ([length]^2 [mass])/[time]^2 | energy
W (watts) | ([length]^2 [mass])/[time]^3 | power

Energy = Power (60) * time (3) = 60 x 3 = 180 Wh

The Attempt at a Solution



If watt-hrs and watts are not compatible how am I supposed to convert these?
 
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You are not expected to convert the 36,000 watt-hr to watts. As you noted, it cannot be done. The power that you need to find is the energy per unit time that this car consumes as it travels at 60 miles per hour.
 
Energy is ususally measured in Joules (J)
Power is the rate of change of energy - ie. how much energy you are using in a given time. Usually measuered in Watts = Joules per second (W = J/s)

so work out how much fuel the car consumes per time unit, then convert that to how much energy per time unit & you have power - pow
 
Last edited:
Correct-o.
 

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