Four equal masses M are spaced at equal intervals, l, along ahorizontal straight rod whose mass can be ignored. The system is tobe rotated about a vertical axis passing through the mass at theleft end of the rod and perpendicular to it.
a) What is the momentof inirtia of the system about this axis?
b) What minimum force, applied to the farthest mass, will impart anangular acceleration, α?
c) What is the direction of this force?