A 50-Kg Crate Is Resting on a Horizontal Plank

question 28

Multiple Choice

A 5.0-kg crate is resting on a horizontal plank.The coefficient of static friction is 0.50 and the coefficient of kinetic friction is 0.40.After one end of the plank is raised so the plank makes an angle of 30° with the horizontal, the force of friction is:

• A)0 N
• B)17 N
• C)20 N
• D)25 N
• E)49 N

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Definitions:

Respondent Behavior

A type of behavior that occurs as an automatic response to a specific stimulus, often reflexive and not under conscious control, such as knee-jerk reactions.

Shaping

A method of teaching new behaviors by rewarding successive approximations of the target behavior.

Reinforcement

In psychology, a stimulus or event that follows a behavior and increases the likelihood of that behavior being repeated.

Shaping

A method of operant conditioning where successive approximations of a desired behavior are reinforced until the exact behavior is achieved.