A Block Is First Placed on Its Long Side and Then

question 20

Multiple Choice

A block is first placed on its long side and then on its short side on the same inclined plane. The block slides down the plane on its short side but remains at rest on its long side. A possible explanation is:

• A) the short side is smoother
• B) the frictional force is less because the contact area is less
• C) the center of gravity is higher in the second case
• D) the normal force is less in the second case
• E) the force of gravity is more nearly down the plane in the second case

---

Definitions:

Muscle Fibers

Muscle fibers are the individual contractile units of muscle tissue, made up of myofibrils and encapsulated in a sarcolemma, that facilitate body movements through contraction and relaxation.

Skeletal Muscle

A type of striated muscle tissue attached to bones, responsible for voluntary movements of the body.

Motor Neurons

Nerve cells that originate in the brain or spinal cord and transmit signals to muscles, inducing movement.

Motor Unit Recruitment

Motor unit recruitment involves the activation of additional motor units to increase the strength of a muscular contraction.