Bicyclists in the Tour de France do enormous amounts of work...

Bicyclists in the Tour de France do enormous amounts of work during a race. For example, the average power per kilogram generated by seven-time-winner Lance Armstrong $(m=75.0 \mathrm{kg})$ is $6.50 \mathrm{W}$ per kilogram of his body mass. (a) How much work does he do during a 135 -km race in which his average speed is $12.0 \mathrm{m} / \mathrm{s} ?$ (b) Often, the work done is expressed in nutritional Calories rather than in joules. Express the work done in part (a) in terms of nutritional Calories, noting that 1 joule $=2.389 \times 10^{-4}$ nutritional Calories.

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Unit Conversion between Joules and Nutritional Calories

This concept pertains to converting energy quantities from one unit system (joules, common in physics) to another (nutritional Calories, common in dietary contexts). Using a specified conversion factor, it bridges the gap between mechanical work and physiological energy intake.

Relationship between Distance, Speed, and Time

This concept involves the formula time = distance/speed, which links the distance traveled with average speed to compute the duration of an activity. It is critical when determining how long energy is expended if the power output is known.

Work

Work is a measure of energy transfer that occurs when a force moves an object over a distance. In mechanics, work is calculated as the product of power and the time over which the force is applied, providing a way to quantify the total energy expended in a process.

Power

Power is the rate at which work is done or energy is transferred. Expressed in Watts (joules per second), it quantifies how quickly energy is used or produced, which is essential for understanding performance in activities requiring sustained output.

Transcript

Please give Ace some feedback