In a Classroom Demonstration,a 79

question 39

Multiple Choice

In a classroom demonstration,a 79.2-kg physics professor lies on a "bed of nails." The bed consists of a large number of evenly spaced,relatively sharp nails mounted in a board so that the points extend vertically outward from the board.While the professor is lying down,approximately 1950 nails make contact with his body.
-What is the average force exerted by each nail on the professor's body?

• A)0.201 N
• B)0.398 N
• C)1.42 N
• D)0.809 N
• E)142 N

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Definitions:

Biceps Brachii

A muscle located in the upper arm responsible for flexing the elbow and supinating the forearm.

Serratus Anterior

A muscle located on the side of the thorax that aids in the movement of the shoulder blade.

Plantar Flexion

A movement that occurs when the toes are pointed downward, decreasing the angle between the foot and the leg.

Eversion

The act of turning inside out or being turned inside out, often used in medical contexts to describe the movement of body parts.