In an Experiment with a Block of Wood on an Inclined

question 42

Multiple Choice

In an experiment with a block of wood on an inclined plane, with dimensions shown in the figure, the following observations are made: (1) If the block is placed on the inclined plane, it remains there at rest. (2) If the block is given a small push, it will accelerate toward the bottom of the incline without any further pushing.
Which one of the following statements is the best conclusion that can be drawn from these observations?

• A)The coefficient of kinetic friction must be negative.
• B)Both coefficients of friction must be less than 0.25.
• C)Both coefficients of friction must be greater than 0.25.
• D)The coefficient of static friction must be less than the coefficient of kinetic friction.
• E)The coefficient of static friction is greater than 0.25 while the coefficient of kinetic friction is less than 0.25.

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