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.
26. Based on the results of Trials 1-8, for a steel block placed on a cast iron surface coated with light machine oil, μ would be:
Your Answer is
Correct Answer is F
Explanation
General knowledge questions.
Look at table 1 first. When the surface composition of inclined plane is cast iron, μ=0.40. After adding oil, μ must be smaller, so finally μ<0.40