Burning Calories While Scuba Diving II

Divers who share this will always see more fish in their dives
    Eduardo Quintana MirandaThis is a guest post from Eduardo Quintana MirandaNuclear Physicist at the Cienfuegos University (Cuba). Eduardo sent me an e-mail right after I have published my “Burning Calories While Scuba Diving” article. He added some notes for me about this topic in an academic way and I have asked him to publish his notes here. I am sharing the e-mail that Eduardo sent me without editing. Eduardo, thank you for your valuable contribution. 

     

    Underwater you might not feel the weight of the equipment (I mean gravitationally speaking), but when you move you do have to spend energy to displace it.

    Your movements underwater can be analyzed in two stages, first when you accelerate (start to move from 0, until V speed is reached); second stage is when you are currently moving at a constant velocity V.

    First stage:
    Work done by you in order to accelerate from 0 to V velocity, must be greater than Eacc=((m+M)*V^2)/2. Where M and m are the mass of your body and gear respectively.

    I said, “Must be greater” because I haven’t taken into consideration the viscosity and friction forces of the water acting upon you.

    Second Stage:
    The energy needed to move some distance X at a constant velocity V, can be written Emov=k*A*V^2*X*D. That is proportional to the effective area of your front (A), squared velocity of movement (V^2), distance travelled (X), and density of the water (D), and some constant (k) depending on your shape.

    Conclusion: The heavier you are, greater the energy spent in accelerations (that is start to move from 0 and reach V speed). The longest the distance travelled, or greater the area of the front, greater energy is spent in constant movement. Most significant of all: the faster your motion speed, a squared greater times of energy you have to spend to move and accelerate (to that speed). So… there’s no need to hurry underwater.

    Divers who share this will always see more fish in their dives

      Speak Your Mind

      *