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Forces on and in the Body
40 Questions
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Forces on and in the Body

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Questions and Answers

What happens to gravity when you let go of a book?

  • Gravity becomes a repulsive force
  • Gravity becomes a balanced force
  • Gravity becomes an unbalanced force (correct)
  • Gravity disappears

    • What are some significant effects of long-term weightlessness on the human body mentioned in the text?

  • Enhanced immune system
  • Improved cardiovascular system functions
  • Increased muscle mass
  • Decreased production of red blood cells (correct)

    • In the human body, what happens when objects are stationary according to the text?

  • The body is accelerating
  • The body experiences dynamic force
  • The body is in a state of equilibrium (correct)
  • The body loses mass

    • How do most skeletal muscles operate according to the text?

    <p>By acting as levers in lever systems</p> Signup and view all the answers

    Which force is responsible for holding the particles in the nucleus of an atom together?

    <p>Strong Nuclear Force</p> Signup and view all the answers

    What is the medical effect of gravitational forces mentioned in the text?

    <p>Formation of varicose veins in the legs</p> Signup and view all the answers

    Which force is responsible for forces resulting from electric charge?

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

    What may happen to a person's bone mineral if they become weightless, such as in an orbiting satellite?

    <p>Loss of bone mineral</p> Signup and view all the answers

    According to Newton's 1st Law of Motion, what happens to an object in motion?

    <p>It remains in motion at constant velocity</p> Signup and view all the answers

    Which of the following forces acts through direct contact between two objects?

    <p>Applied Forces</p> Signup and view all the answers

    How does Newton's 2nd Law relate force to mass and acceleration?

    <p>$\text{Force} = \text{mass} \times \text{acceleration}$</p> Signup and view all the answers

    What is the main idea behind Newton's 3rd Law of Motion?

    <p>Every force has an equal and opposite reaction force</p> Signup and view all the answers

    What is the main function of the muscular forces described in the text?

    <p>To cause blood circulation and lung air intake</p> Signup and view all the answers

    Which force is responsible for the formation of varicose veins in the legs as mentioned in the text?

    <p>Gravitational Force</p> Signup and view all the answers

    What is the medical impact on bone mineral when a person undergoes long-term bed rest according to the text?

    <p>Bone mineral decreases</p> Signup and view all the answers

    Which force gives materials their strength, their ability to bend, squeeze, stretch, or shatter?

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

    What is the impact on bone mineral when a person becomes weightless, such as in an orbiting satellite?

    <p>Bone mineral decreases</p> Signup and view all the answers

    Which force holds the particles in the nucleus of an atom together?

    <p>Strong Nuclear Force</p> Signup and view all the answers

    What causes the radioactive decay of nuclei according to the text?

    <p>Strong Nuclear Force</p> Signup and view all the answers

    Which force is very large compared to gravity and is responsible for forces resulting from electric charge?

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

    In a second-class lever, where is the point of resistance located?

    <p>Between the fulcrum and effort</p> Signup and view all the answers

    What is the role of muscle contraction in a bone-muscle lever system?

    <p>Provides effort at the insertion on the bone</p> Signup and view all the answers

    Which type of lever has the pivot located between the effort and the load?

    <p>First-class lever</p> Signup and view all the answers

    What is a mnemonic to remember levers based on their types?

    <p>123 FLE</p> Signup and view all the answers

    What does mechanical advantage refer to in lever systems designed for force?

    <p>Decreasing force required</p> Signup and view all the answers

    How is a second-class lever utilized in the human body?

    <p>When standing on tip-toe</p> Signup and view all the answers

    What determines the mechanical advantage of levers in general?

    <p>Effort arm divided by resistance arm</p> Signup and view all the answers

    Which lever type allows a given effort to move a heavier load than it otherwise could?

    <p>Second-class lever</p> Signup and view all the answers

    What is the force developed when a person's head, with a mass of 4 Kg, stops in 0.5 cm in about 0.01 sec after hitting a steel beam at 1 m/sec?

    <p>400 Newton</p> Signup and view all the answers

    What is the acceleration experienced by the person's head when it stops in 0.5 cm in about 0.01 sec after hitting a steel beam at 1 m/sec?

    <p>400 m/sec²</p> Signup and view all the answers

    Which effect mentioned in the text is related to changes in internal hydrostatic pressure due to acceleration?

    <p>Changes in internal hydrostatic pressure</p> Signup and view all the answers

    What is the resonant frequency of an organ directly dependent on according to the text?

    <p>Mass and elastic forces acting on it</p> Signup and view all the answers

    In order for the spine to be in equilibrium when lifting a weight with a horizontal back, what must happen?

    <p>The torque due to the muscles must balance the torque due to the weights.</p> Signup and view all the answers

    Why does lifting a weight incorrectly, with the back horizontal, result in so many back injuries?

    <p>The muscles must exert a force of more than 1000 N to balance the torque.</p> Signup and view all the answers

    When lifting a weight against your body, why does it exert a smaller torque compared to lifting it with the back horizontal?

    <p>The weight is held closer to the body.</p> Signup and view all the answers

    How does the torque exerted by a 10 kg weight lifted against your body compare to the same weight lifted with the back horizontal?

    <p>It is about 10 N.</p> Signup and view all the answers

    What happens to the torque when you hold the weight closer to your body while lifting it?

    <p>The torque decreases.</p> Signup and view all the answers

    Why do muscles need to exert a large force when balancing torques due to weights on the spine?

    <p>To ensure no net force acts on the spine.</p> Signup and view all the answers

    What can be inferred about weightlifting with knees bent and back straight based on the text?

    <p>It exerts little torque on the spine.</p> Signup and view all the answers

    How does holding a weight closer to your body affect the torque it exerts according to the text?

    <p>'Closer' reduces the lever arm, hence decreases the torque.</p> Signup and view all the answers

    Study Notes

    • A force is a push or pull acting on an object that changes its motion.
    • Types of forces: contact forces (applied forces, friction) and field forces (gravity, electromagnetic force).
    • Contact forces require physical contact between objects.
    • Field forces act through empty space.
    • Newton's Laws of Motion:
      • 1st Law (Law of Inertia): an object will stay at rest or in motion at constant velocity unless acted upon by an unbalanced force.
      • 2nd Law: force equals mass times acceleration.
      • 3rd Law: for every action, there is an equal and opposite reaction.
    • Four fundamental forces in nature:
      • Gravitational Force: an attractive force that exists between all objects; weakest force.
      • Electromagnetic Force: results from electric charge; very large compared to gravity.
      • Strong Nuclear Force: holds particles in the nucleus of an atom; strongest force but only acts over a short distance.
      • Weak Force: a form of electromagnetic force involved in radioactive decay.
    • Forces in and on the body:
      • Muscular forces cause blood circulation and lung function.
      • Molecular forces exist in bone and calcium atoms.
      • Electric forces exist in the body.
      • Gravitational forces affect medical conditions like varicose veins and bone loss.
    • Effects of gravity on the body and medical conditions.
    • Lever Systems:
      • Levers consist of a beam or rigid rod pivoted at a fixed hinge or fulcrum.
      • Levers divide into three types based on the location of the fulcrum, load, and effort.
      • In the human body, bones act as levers, joints as fulcrums, and muscle contractions provide effort.
    • Mechanical advantage and mechanical disadvantage in levers.
    • Mechanical advantage formula: MAlever = Effort (force) arm / Resistance (load) arm.
    • Example: lifting a weight with the back horizontal exerts a larger torque and requires greater force from muscles compared to lifting the same weight while keeping back straight.

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    Description

    This quiz explores the concept of forces acting on objects and within the body. It covers different types of forces such as applied forces, friction, gravity, and electromagnetic forces.

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