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Transcribed Image Text:On your bike, you start from rest and accelerate to the
speed of 5 m/s in 20 s (assume constant acceleration),
and keep going at this speed on a level ground for
further 500 m. During your trip, the average air drag
force on you is 13 N, and the rolling friction force is
9 N. Assume 75 kg total mass of yourself and the bike,
20% mechanical energy efficiency in your body, and a
BMR of 100 W. How much Calories you have spent to
accomplish this?
Draw the energy model of the situation!
k
Hint: "Average air drag force" means that you can use
the same value of the air drag over the whole travle
distance, for both acceleration stage and motion with a
constant speed. We know that the air drag force in fact
depends on speed, but since the average value i
you do not need to care about it.
Calculat
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