24 Questions
In a third-class lever, the external weight always has greater leverage than the muscle force.
False
Third-class levers are the least common type of lever in the musculoskeletal system.
False
Third-class levers provide high forces that can be used to stabilize the joint effectively.
False
In a third-class lever, the mechanical advantage is always greater than 1.
False
Vector resolution is the process of replacing two or more forces with a single force that is equivalent to the original forces.
False
The rotatory component in a third-class lever acts parallel to a bony segment.
False
The translatory component in a third-class lever compresses and stabilizes the joint.
False
A free body diagram includes forces like Sy, Wx, and S.
False
Musculoskeletal forces applied to the body can only cause translation of a body segment.
False
The moment arm (D) is the shortest distance between the force (F) and the axis of rotation (AoR).
True
Torque (T) is the product of the force (F) and the moment arm (D).
True
The internal moment arm (IMA) is the distance between the joint's axis of rotation and the effective site of external force application.
False
The external moment arm (EMA) is the distance between the joint's axis of rotation and the effective internal force.
False
The equation $IF \times D = EF \times D_1$ is always true.
True
The internal torque is always equal to the external torque.
True
The majority of human movement is translational, not rotational.
False
In a first-class lever, the axis of rotation is positioned between the opposing forces.
True
The head is held in equilibrium when the product of muscle force (MF) and internal moment arm (IMA) equals the product of head weight (HW) and external moment arm (EMA).
True
In a first-class lever, the internal and external forces act in the same linear direction.
True
The mechanical advantage of the first-class lever example given in the text is 0.8.
False
In a second-class lever, the axis of rotation is located at one end of a bone.
True
The calf muscles are an example of a second-class lever.
True
In a second-class lever, the muscle force has less leverage than the external force.
False
Second-class levers are common in the musculoskeletal system.
False
Test your knowledge on third-class levers in the musculoskeletal system, with a focus on its features, examples, and advantages. Understand how muscles function as compared to external weights in this lever arrangement.
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