A Friction Force

question 114

Multiple Choice

A friction force

• A) is a contact force that acts parallel to the contact surfaces.
• B) is a normal force between contact surfaces.
• C) is a scalar quantity since it can act in any direction along a surface.
• D) does not depend on the nature of the surfaces.

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Definitions:

Heart

A muscular organ in most animals, which pumps blood through the blood vessels of the circulatory system by rhythmic contraction and dilation.

Arrector Pili

Small muscles connected to hair follicles that, when contracted, cause hair to stand up, producing 'goosebumps'.

Goose Bumps

The raising of small bumps on the skin due to the contraction of miniature muscles at the base of hair follicles, usually in response to cold or fear.

Hair Follicles

The skin organ that produces hair, consisting of a small tubular cavity containing the root of a hair and located in the dermis of the skin.