A Uniform Plank XY Is Supported by Two Equal 120-N

question 5

Multiple Choice

A uniform plank XY is supported by two equal 120-N forces at X and Y, as shown.The support at X is then moved to Z (half-way to the plank center) .The supporting forces at Y and Z are then:

• A)F_Y = 240 N, F_Z = 120 N
• B)F_Y = 200 N, F_Z = 40 N
• C)F_Y = 40 N, F_Z = 200 N
• D)F_Y = 80 N, F_Z = 160 N
• E)F_Y = 160 N, F_Z = 80 N

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Definitions:

Positive Feedback

Mechanism of homeostatic response in which the output of the system intensifies and increases the activity of the system.

Negative Feedback

Mechanism of homeostatic response by which the output of a system suppresses or inhibits activity of the system.

Metabolic Rate

The rate at which energy is expended by the body to maintain basic physiological functions and to perform activities.

Thyroid

A gland in the neck that produces hormones regulating the body's metabolic rate as well as heart and digestive function, muscle control, brain development, and bone maintenance.