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Suppose your body was able to use the chemical energy in gasoline. How far could you pedal a bicycle at 15 km/h on the energy in 1.0 gal of gas? (1 gal of gas has a mass of 3.2 kg.)

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6 votes

Final answer:

If our bodies were able to use gasoline with 20% efficiency, we could pedal a bicycle at 15 km/h for approximately 1083.3 kilometers on the energy contained in 1 gallon of gasoline.

Step-by-step explanation:

To estimate how far you could pedal a bicycle on the energy contained in 1.0 gallon of gasoline, we consider the energy content of the gasoline and the efficiency of a human bicycling. One gallon of gasoline contains approximately 130 megajoules (MJ) of energy. The average person cycling at a moderate effort level may be about 20% efficient at converting food energy to mechanical energy. For simplicity, we'll assume that if our bodies could use gasoline, we'd also be 20% efficient with it.

The energy used by a cyclist pedal at 15 km/h is far less than the energy content of 1 gallon of gasoline. If we assume that biking at 15 km/h requires roughly 100 watts of power, this translates to 0.1 kilowatts. Therefore, to find out how long the 130 MJ of gasoline could last, we convert it to kilowatt-hours (kWh), where 1 MJ equals 0.2778 kWh. This gives us approximately 36.11 kWh for the energy in 1.0 gallon of gasoline.

If our bodies were 20% efficient, we'd effectively use 0.2 x 36.11 = 7.222 kWh of that energy. Since power is energy over time, and we want to know the time, we rearrange the equation for time, giving us time = energy/power. This amounts to 7.222 kWh / 0.1 kW, which equals 72.22 hours of cycling. Finally, by multiplying the cycling time by the speed, i.e., 72.22 hours x 15 km/h, we find that one could pedal 1083.3 kilometers on the energy content of 1 gallon of gasoline when cycling at 15 km/h.

User Yoichiro
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3 votes

The distance you will travel, suppose your body was able to use the chemical energy in gasoline is 0.89 m

How to calculate the distance you will travel?

First, we shall calculate the kinetic energy of your body. details below:

  • Volume of gasoline = 1.0 gallon = 3.2 Kg
  • Mass (m) = Volume of gasoline = 1.0 gallon = 3.2 Kg
  • Velocity (v) = 15 km/h = 15 / 3.6 = 4.17 m/s
  • Kinetic energy (KE) =?

KE = ½mv²

= ½ × 3.2 × 4.17²

= 27.82 J

Finally, we shall calculate the distance. Details below:

  • Kinetic energy (KE) = 27.82 J
  • Work done = Kinetic energy (KE) = 27.82 J
  • Mass (m) = 3.2 kg
  • Acceleration due to gravity (g) = 9.8 m/s²
  • Force (F) = mg = 3.2 × 9.8 = 31.36 N
  • Distance traveled =?

Work done = Force × Distance

Distance = work done / force

= 27.82 / 31.36

= 0.89 m

User Anatoly Deyneka
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