Energy , Work , and power of Human Body
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Questions and Answers

What is the concept of energy that remains fixed in any process that occurs in nature?

  • Conservation of mass
  • Conservation of momentum
  • Conservation of energy (correct)
  • Conservation of velocity

    • What is the symbol for the stored energy in the body?

  • ΔW
  • ΔQ
  • Δt
  • ΔU (correct)

    • What happens to a body that is doing no work and at a constant temperature?

  • It loses heat to the surrounding environment (correct)
  • It gains heat from the surrounding environment
  • It does work at a constant rate
  • It remains at a constant temperature

    • What is the rate of doing work in the body?

    <p>P</p> Signup and view all the answers

    What is the equation that relates the change in stored energy, heat lost, and work done by the body?

    <p>ΔU = ΔQ - ΔW</p> Signup and view all the answers

    What is the unit of Δt?

    <p>Seconds</p> Signup and view all the answers

    What is the measure of the human body's ability to do work?

    <p>Energy</p> Signup and view all the answers

    What unit is used to express food energy?

    <p>Kilocalories</p> Signup and view all the answers

    What is the unit of energy in the SI system?

    <p>Joule</p> Signup and view all the answers

    What is the unit of power in the SI system?

    <p>Watt</p> Signup and view all the answers

    What is the unit of expressing the rate of energy consumption of the body?

    <p>Metabolic Equivalents</p> Signup and view all the answers

    What is the conversion of 1 erg in Joule?

    <p>1 erg = 10^(-7) J</p> Signup and view all the answers

    What happens when your body's internal energy is lost in a short time interval?

    <p>You tend to feel tired</p> Signup and view all the answers

    Why does cycling require less energy than running?

    <p>Because cycling has less gravitational potential energy to overcome</p> Signup and view all the answers

    What is the purpose of sweating when your body does much work?

    <p>To lose excess heat</p> Signup and view all the answers

    What provides the energy necessary for muscle contraction?

    <p>The energy released by chemical reactions</p> Signup and view all the answers

    What happens to the body's internal energy when you consume food?

    <p>It increases</p> Signup and view all the answers

    What is the result of the energy released by chemical reactions in the body?

    <p>Both work and heat are generated</p> Signup and view all the answers

    What is the primary reason why your bike would gradually slow down if you did not pedal at all?

    <p>Because of the friction</p> Signup and view all the answers

    What happens to the kinetic energy of a runner when their body moves downward?

    <p>It decreases</p> Signup and view all the answers

    What is the characteristic of more efficient runners?

    <p>They bob up and down less</p> Signup and view all the answers

    Why does a runner's center of mass continually alternate between speeding up and slowing down?

    <p>Because of the stride motion</p> Signup and view all the answers

    What happens to the gravitational potential energy of a runner when they move upward?

    <p>It increases</p> Signup and view all the answers

    What is the main difference between riding a bike and running on a flat surface?

    <p>The constancy of kinetic energy</p> Signup and view all the answers

    What is the primary purpose of the body's temperature regulation mechanisms?

    <p>To maintain a constant body temperature despite environmental fluctuations</p> Signup and view all the answers

    What type of radiation does the body emit?

    <p>Electromagnetic radiation</p> Signup and view all the answers

    What is the approximate value of the radiation coefficient (𝐾𝐾𝑟𝑟)?

    <p>5 kcal/m2.hr.˚C</p> Signup and view all the answers

    What is the formula for heat loss due to radiation (𝐻𝐻𝑟𝑟)?

    <p>𝐻𝐻𝑟𝑟 = 𝐴𝐴𝑟𝑟 × 𝐾𝐾𝑟𝑟 × (𝑇𝑇𝑠𝑠 - 𝑇𝑇𝑤𝑤)</p> Signup and view all the answers

    What is the primary factor that affects the convection coefficient (𝐾𝐾𝑐𝑐)?

    <p>Movement of the air</p> Signup and view all the answers

    What is the heat loss due to convection (𝐻𝐻𝑐𝑐) proportional to?

    <p>The difference between the skin temperature and the wall surrounding temperature</p> Signup and view all the answers

    Muscles consist of bundles of protein filaments.

    <p>False</p> Signup and view all the answers

    When a muscle contracts, it generates a force that acts through a distance.

    <p>True</p> Signup and view all the answers

    The energy used by the body when muscles contract is always in the form of kinetic energy.

    <p>False</p> Signup and view all the answers

    The work done by the biceps muscle is equal to the work done by the force the hand exerts on the weight.

    <p>True</p> Signup and view all the answers

    The heat generated by the body when muscles contract is always equal to the work done by the muscles.

    <p>False</p> Signup and view all the answers

    When you hold a weight in your hand and contract the biceps muscle in your arm, the weight's gravitational potential energy decreases.

    <p>False</p> Signup and view all the answers

    Muscles can only contract in one direction.

    <p>False</p> Signup and view all the answers

    The energy used by the body when muscles contract is always used to move one of the body's limbs.

    <p>False</p> Signup and view all the answers

    Muscles can convert all the energy they use into work.

    <p>False</p> Signup and view all the answers

    The work done by muscles is always proportional to the force they exert.

    <p>False</p> Signup and view all the answers

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