Although this measurement, by itself, can be an interesting
laboratory exercise for students in an introductory mechanics
course, a somewhat richer experience can be derived by combining
it with another, more traditional method of determining
ms, so that a direct comparison of the results can be made.
One such technique is illustrated in Fig. 1(b), in which (possibly)
the same surface used in the slipping/tipping method is
slowly and precisely elevated with a lab jack until the angle θ
reaches the critical (slip) value θs at which the block just begins
to slide down the incline. Balancing the forces on the stationary
block with the static friction force set to its maximum
yields the simple result1 for the static friction coefficient: