Passage V
A block is placed on an inclined plane, as shown in Figure 1.
The angle of inclination is increased. The angle at which static friction is overcome and the block starts to slide is αc, the critical angle for sliding. The amount of static friction to be overcome depends on µ, the coefficient of static friction.
Table 1 gives αc and µ for a steel block sliding on various uncoated surfaces at 20°C. Tables 2 and 3 give αc and µ for the steel block sliding on a steel surface coated with various oils at 20°C and 100°C, respectively.
24. Based on the passage and the data an Tables 1-3, to start the block sliding down the inclined plane, the greatest amount of force was required in:
Your Answer is
Correct Answer is G
Explanation
The larger the coefficient of friction μ, the less likely the block will move, so it should be trail 4, μ=0.80