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How many miles/bagel do you get?: solving for W/kcal

Updated: Oct 9, 2023

W/kcal = watt per kilocalorie = energy from food = E/C (electrons from carbon

)


The amount of torque required to turn a 1 horsepower electric motor at 100 RPMs depends on the design of the motor and the load it is driving. However, we can calculate an approximate value based on some assumptions. Assuming that the electric motor is operating at 100% efficiency (which is not possible in reality), we can use the following formula to calculate the torque: Torque (in foot-pounds) = (1 horsepower x 5252) / RPM. Plugging in the values, we get: Torque = (1 x 5252) / 100 Torque = 52.52 foot-pounds Approximately 52.52 foot-pounds of torque will be needed to turn a 1 horsepower electric motor at 100 RPMs, assuming 100% efficiency. The actual torque required will be higher due to losses in the motor and the load it is driving. To calculate the RPM required to produce 52 foot-pounds of torque on a bicycle with a gearing of an 11-tooth sprocket and a 52-tooth chainring, we need to consider the gear ratio and the mechanical advantage of the bicycle. The gear ratio is the ratio of the number of teeth on the front chainring to the number of teeth on the rear sprocket. In this case, the gear ratio is Gear Ratio = Number of teeth on chainring / Number of teeth on rear sprocket Gear Ratio = 52 / 11 Gear Ratio = 4.73 The mechanical advantage of the bicycle is the ratio of the force applied to the pedals to the force transmitted to the rear wheel. Assuming no losses due to friction or air resistance, the mechanical advantage is equal to the gear ratio. So, the mechanical advantage in this case is also 4.73. To calculate the RPM required to produce 52 foot-pounds of torque, we can use the following formula: RPM = (Torque x Mechanical Advantage) / (2 x pi x Pedaling Cadence). Assuming a rider weight of 200 pounds and a gravitational acceleration of 32.2 feet per second squared, the force required to move the bicycle at a constant speed on flat ground is approximately: Force = Rider Weight x Gravitational Acceleration Force = 200 x 32.2 Force = 6440 pounds. The torque required to produce this force on a bicycle with a 52-tooth chainring and an 11-tooth sprocket is approximately: Torque = Force x Chainring Radius Torque = Force x (Chainring Diameter / 2) Torque = 6440 x (4.33 / 2) Torque = 13973.4 inch-pounds Torque = 1164.45 foot-pounds (dividing by 12 to convert to foot-pounds).Plugging in the values, we get: RPM = (52 x 4.73 x 1) / (2 x pi x 1164.45 / 12) RPM = 33.3. To pedal at approximately 33.3 RPMs to produce 52 foot-pounds of torque on a bicycle with a gearing of a 11-tooth sprocket on the rear cassette and a 52-tooth chainring on the cranks, assuming flat ground, no wind, and no losses due to friction or air resistance. To calculate the amount of electrical power that can be generated by the 1 horsepower electric motor attached to a stationary bicycle trainer, we need to consider the mechanical power output of the motor, the efficiency of the motor, and the efficiency of the power conversion system (battery, inverter, and meter adapter). First, we need to calculate the mechanical power output of the motor. We can use the following formula to calculate mechanical power: Mechanical Power = Torque x Angular Velocity. We know from the previous question that the torque required to produce 1 horsepower at 100 RPMs is approximately 52.52 foot-pounds. We also know that the angular velocity (in radians per second) at 100 RPMs is: Angular Velocity = 100 x 2 x pi / 60 Angular Velocity = 10.47 radians per second. The mechanical power output of the motor is: Mechanical Power = 52.52 x 10.47 Mechanical Power = 549.22 foot-pounds per second. To convert foot-pounds per second to watts, we can multiply by 1.35582: Mechanical Power = 549.22 x 1.35582 Mechanical Power = 744.45 watts. This is the theoretical maximum mechanical power output of the motor. The efficiency of the motor is less than 100%, so the actual mechanical power output will be lower. Let's assume an efficiency of 80%, which means that 80% of the input electrical power is converted to mechanical power. This gives us: Actual Mechanical Power = 744.45 x 0.8 Actual Mechanical Power = 595.56 watts. Consider the efficiency of the power conversion system. Let's assume an overall efficiency of 70%, which considers losses due to battery charging, DC-AC conversion, and metering. This gives us: Electrical Power Output = Actual Mechanical Power x Efficiency Electrical Power Output = 595.56 x 0.7 Electrical Power Output = 416.89 watts. 1 horsepower electric motor attached to the stationary bicycle trainer is pedaled at 100 RPMs for one hour, it can generate approximately 416.89 watts of electrical power, assuming an efficiency of 80% for the motor and an overall efficiency of 70% for the power conversion system. As of September 2021, the average price per kilowatt-hour (kWh) for residential customers in California is approximately 23.41 cents. However, it's important to note that electricity rates can vary depending on the specific utility company and location within California. Additionally, the time of day, season, and electricity usage can also impact the price per kWh. To get the most accurate and up-to-date information on electricity rates in California, it's recommended to check with the specific utility company that services your area or visit the California Public Utilities Commission website. To calculate how much money can be made by selling back electricity generated by riding a bike for 2 hours a day, 5 days a week for a month, we need to make a few assumptions based on the information provided. From the previous calculations, we know that riding the bike at 100 RPM for 2 hours generates approximately 1.67 kilowatt-hours (kWh) per day. Assuming that the net metering buyback rate is the same as the average price per kWh for residential customers in California, which is approximately 23.41 cents as of September 2021, we can calculate the total earnings for the month. Total electricity generated in a month = 1.67 kWh/day x 5 days/week x 4 weeks/month = 33.4 kWh Total earnings for the month = Total electricity generated x Net metering buyback rate Total earnings for the month = 33.4 kWh x $0.2341/kWh = $7.81. Therefore, if the bike was ridden at 100 RPM for 2 hours a day, 5 days a week for a month, and the electricity generated was sold back to the electric company using net metering buyback, the total earnings for the month would be approximately $7.81. It's worth noting that this calculation is based on ideal conditions and does not consider any additional factors that may affect the actual amount of electricity that can be generated or sold back. The average cost of a coffee and doughnut in Southern California can vary depending on the specific location, type of establishment, and other factors. However, based on current prices at popular chains in the area, a basic cup of coffee and a doughnut can cost around $3 to $5 on average. It's worth noting that prices can vary depending on the size of the coffee, the type of doughnut, and whether any additional items are added to the order. Additionally, prices at independent or local coffee shops and bakeries may differ from those at larger chains. The amount of time a person would need to ride a bike to generate enough watts to sell back to the electric company using net metering buyback would depend on a few factors, including the size of the battery, the efficiency of the inverter, and the amount of electricity the person wants to sell back. Let's assume that the battery has a capacity of 10 kilowatt-hours (kWh), and the inverter has an efficiency of 90%. If the person wants to sell back 1 kWh of electricity, they will need to generate 1.11 kWh of electrical power (due to losses in the inverter). 1 horsepower electric motor attached to a stationary bicycle trainer, pedaled at 100 RPMs, can generate approximately 416.89 watts of electrical power, assuming an efficiency of 80% for the motor and an overall efficiency of 70% for the power conversion system. To generate 1.11 kWh of electrical power, the person would need to pedal for: Time = Energy / Power Time = 1.11 kWh / (416.89 watts x 0.8 x 0.7) Time = 2.33 hours. Pedaling for approximately 2.33 hours to generate enough watts to sell back 1 kWh of electricity to the electric company using net metering buyback, assuming the battery has a capacity of 10 kWh, and the inverter has an efficiency of 90%. It's worth noting that this calculation is based on ideal conditions and does not consider any additional factors that may affect the actual amount of electricity that can be generated or sold back. Calculating the exact number of calories burned while cycling can be challenging, as it depends on many factors, such as intensity, duration, body weight, and metabolic rate. However, we can make some estimates based on the information you provided. A 200 lb (90.7 kg) man who is 6 ft (1.83 m) tall and active, we can estimate your daily caloric needs based on your activity level. According to the Harris-Benedict equation, which is commonly used to estimate basal metabolic rate (BMR) and total daily energy expenditure (TDEE), your estimated TDEE is around 2800-3200 calories per day, depending on your age, sex, and other factors. At 70% of your perceived effort, we can estimate the number of calories burned per hour based on your body weight and the intensity of exercise. A general estimate is that cycling at a moderate intensity can burn around 400-500 calories per hour for someone who weighs 200 lbs. The approximate number of calories you would burn per hour while cycling at 70% perceived effort would be: 400-500 calories/hour x 0.7 = 280-350 calories/hour This is an estimate, and the actual number of calories burned could be different based on factors such as fitness level, efficiency of pedaling, and terrain. Also, keep in mind that this estimate only applies to the time spent cycling, and your total daily caloric needs will depend on other factors such as your BMR and overall activity level. The number of kilocalories (kcal) in a bagel can vary depending on the size and type of bagel. On average, a plain, medium-sized bagel can contain around 250-300 kcal. However, some larger or flavored bagels can have up to 400-500 kcal or more. To burn off the number of calories in a bagel, you would need to engage in physical activity that burns calories. The amount of time it would take to burn off the calories in a bagel depends on the type of activity, the intensity, and your body weight. Here are some estimates based on a few common physical activities:Running at a moderate pace (6 mph): approximately 30 minutes to burn off 250-300 kcal, or up to 45-60 minutes for larger or flavored bagels.Cycling at a moderate pace (14-16 mph): approximately 25-30 minutes to burn off 250-300 kcal, or up to 40-50 minutes for larger or flavored bagels. Swimming at a moderate pace: approximately 35-45 minutes to burn off 250-300 kcal, or up to 60-75 minutes for larger or flavored bagels. These are estimates based on average calorie burn rates and will vary depending on individual factors. It's also important to note that physical activity alone is not the only factor in maintaining a healthy weight and diet.


Artist: Travis Stone


Works cited:

1. NREL (National Renewable Energy Laboratory). (2021). Net Metering. Retrieved from https://www.nrel.gov/energy-efficiency/net-metering.html This source provides an overview of net metering, including what it is, how it works, and the benefits and challenges associated with it. It is a reliable source of information as it is published by the National Renewable Energy Laboratory, a research laboratory funded by the U.S. Department of Energy.

2. EIA (U.S. Energy Information Administration). (2021). Average Price of Electricity to Ultimate Customers by End-Use Sector. Retrieved from https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a This source provides data on the average electricity prices for residential customers in California. It is a reliable source of information as it is published by the U.S. Energy Information Administration, an independent statistical agency.

3. Carbonfootprint.com. (2021). Home Energy Calculator. Retrieved April 24, 2021, from https://www.carbonfootprint.com/calculator.aspx This website provides an easy-to-use calculator that allows users to calculate the carbon footprint of their home energy usage. It includes information on the type of energy used, the number of people living in the home, and the type of appliances used. The calculator also provides tips on how to reduce energy consumption in the home.

4. California Public Utilities Commission. (n.d.). Residential Rate Schedules. Retrieved April 24, 2021, from https://www.cpuc.ca.gov/residentialrates/ This website provides up-to-date information on the residential electricity rates in California. It includes information on the rates charged by specific utility companies, as well as the different rate schedules available. It also provides information on how to compare rates and how to switch to a lower rate.

5. Siegenthaler, J. (2020). Understanding Motor Efficiency. Retrieved April 24, 2021, from https://www.allaboutcircuits.com/technical-articles/understanding-motor-efficiency/

California Public Utilities Commission. (2021). Residential Rates and Charges. Retrieved from https://www.cpuc.ca.gov/residentialrates/

6. Cramer, H. (2018). Understanding Electric Motor Efficiency Ratings. Retrieved from https://www.baldor.com/en-us/mro/pages/mro-understanding-electric-motor-efficiency-ratings.aspx

7. Engineering Toolbox. (n.d.). Power Calculations for Mechanical Systems. Retrieved from https://www.engineeringtoolbox.com/power-mechanical-systems-d_1226.html

8. US Energy Information Administration. (2021). Electric Power Monthly. Retrieved from https://www.eia.gov/electricity/monthly/

9. United States Department of Energy. (n.d.). Electricity prices. Retrieved from https://www.eia.gov/electricity/prices/

10. California Public Utilities Commission. (2021, September). 2020-2021 electricity rates. Retrieved from https://www.cpuc.ca.gov/2020-2021-electricity-rates/

11. Hsieh, C. (2020, August 21). How to calculate torque. Retrieved from https://www.machinemfg.com/how-to-calculate-torque/

12. Hunter, T. (2020, August 11). Bicycle gear ratios: How to select the right one. Retrieved from https://www.bicycling.com/maintenance/bicycle-gear-ratios-how-to-select-the-right-one

13. McLeod, S. (2021, June 21). How to calculate power output of an engine. Retrieved from https://www.machinemfg.com/how-to-calculate-power-output-of-an-en


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