Biomechanics
What is the reason that a third-class lever is inefficient?
The muscle’s effort force is applied closer to the fulcrum than the load force.
The load force is applied closer to the fulcrum than the muscle’s effort force.
The fulcrum separates the effort from the load.
The load force is greater than the muscle’s effort force.
The muscle’s effort force is applied closer to the fulcrum than the load force.
Consider flexing the forearm using the biceps brachii. Its tendon is inserted on the radius bone very close to the elbow joint, while the load (the forearm) is further away. Such an arrangement allows a short contraction of the biceps brachii to be converted to a large sweep of motion of the hand.
The muscle’s effort force is applied closer to the fulcrum than the load force. Consider flexing the forearm using the biceps brachii. Its tendon is inserted on the radius bone very close to the elbow joint, while the load (the forearm) is further away. Such an arrangement allows a short contraction of the biceps brachii to be converted to a large sweep of motion of the hand.
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When two forces of magnitude 6 N and 10 N are added vectorially, what value could the resulting vector NOT have?A. 4 N
B. 6 N
C. 10 N
D. 18 N
Which of the following is not an example of a force?
A. Tension
B. Friction
C. Inertia
D. Weight
What is the purpose of using a slide sheet in patient manual handling?
A. To extend the patient’s base of support
B. To facilitate raising the patient’s centre of gravity
C. To minimise friction between the patient and the bed
D. To minimise the patient’s inertia
Traction forces may be represented by vectors. In Hamilton-Russell traction, which of the following vectors is equal in magnitude to the traction force?
A. The component of the patient’s weight that is perpendicular to the bed
B. The component of the patient’s weight that is parallel to the bed
C. The vector in A subtracted from the patient’s weight
D. The resulting vector when the vectors in A and B are added
What does the term “friction” refer to?
A. The tension force generated when a muscle contracts
B. A force that acts in the opposite direction to a motion
C. The resistance force that is overcome by an effort force
D. The force of gravity that causes an object to fall
When the biceps brachii muscle flexes the forearm, what is the forearm an example of?
A. A first-class lever
B. A second-class lever
C. A third-class lever
D. An efficient lever
Third-class lever systems are always inefficient for which one of the following reasons?
A. The effort arm is longer than the load arm.
B. The effort force required is less than the load force.
C. The fulcrum lies between the effort and the load. The load arm is longer than the effort arm.
D.
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