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16 Cards in this Set
- Front
- Back
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What is a lever?
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A rigid, elongated object that rotates around a fixed point (fulcrum).
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When does rotation occur for a lever?
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When the effort exerted on a certain point of the lever is GREATER than the resistance at another point on the lever.
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What is the load?
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The resistance. The PART of the lever from the fulcrum to the point of resistance is the resistance arm.
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What is the force?
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The effort. The part of the lever from the effort to the fulcrum is the effort arm. In the body effort is exerted by muscles.
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What do D(F) & D(L) stand for?
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D(F) = Distance (Force) it is = effort arm
D(L) = Distance (Resistance) = resistance arm |
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What is the most common lever system found in the body? What is the least common?
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The most common - 3rd class - elbow
(the effort is in the middle) The least common is 2nd class - Pla. F. (the resistance is in the middle) |
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What is the best lever class system to use when you want to pick up something heavy without a lot of force?
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The 2nd class lever system b/c a small force/effort can balance a larger weight if the resistance is closer to the fulcrum. You need a LONGER FORCE ARM!!
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What is the difference in load & force arms in 2nd and 3rd class systems?
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2nd class = LONGER FORCE ARM
(shorter load arm) 3rd class = LONGER LOAD ARM (shorter force arm) |
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What is the equation of the force/load?
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D(L)xL = D(F)xF
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What is the difference between the book and the notes in terms of the equation?
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The book has the mass of the load + force as Kilograms & her notes has them in Newtons instead of mass.
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What is amplified by the lever system?
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Velocity(speed) and Range of Movement.
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What kind of force/effort arm does the elbow exhibit?
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The elbow exhibits a SHORT force arm.
3rd class lever system |
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How are our body's disadvantaged in terms of lever systems?
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The most efficient lever system to lift heavy loads is 2nd class with a long force arm. Our bodies typically have mostly 3rd class with a long load arm.
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How do our bodies help to compensate for the disadvantage in terms of strength?
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PENNATION - when the muscle fibers run diagonally they increase the number of fibers per volume of muscle. Pennation INCREASES STRENGTH
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By having a short force arm the body sacrifices a lot of its strength in terms of lever class systems, what does this sacrifice gain?
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Maneuverability is gained by the body sacrificing strength w/ a short force arm.
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What is the calculation of converting kg into newtons?
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Force = Mass x Acceleration
9.81m/sec^2 |
