How to solve how much work is done:

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Bicyclists in the Tour de France perform significant work, exemplified by Lance Armstrong's average power output of 6.50 W/kg during a race. To calculate the work done over an 80-km race at an average speed of 12.0 m/s, the time taken for the race must first be determined. This can be calculated using the formula time = distance/speed. Additionally, the work done can be converted from joules to nutritional Calories, with the conversion factor of 1 joule equaling 2.389 x 10^-4 nutritional Calories. The discussion emphasizes the importance of understanding both the physical calculations and nutritional implications of the work done by athletes.
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Bicyclists in the Tour de France do enormous amounts of work during a race. For example, the average power per kilogram generated by Lance Armstrong (m = 75.0 kg) is 6.50 W per kilogram of his body mass.
(a) How much work does he do during a 80-km race in which his average speed is 12.0 m/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 10-4 nutritional Calories.

p=w/t
Ke=1/2 mv^2
w+Kef-Kei

I started with plugging the information I was given into the problems above, but got stuck after that.
 
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For part (a) how long did the race last (for him, anyway)?
 

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