A rope of length πΏ and uniform linear density π is hanging over the edge of a table such that the vertically
hanging piece has a length π₯0 at time π‘ = 0. The position of the bottom end of the rope, i.e. point π, with
respect to the edge of the table is given at time π‘ by π₯(π‘). Initially (at π‘ = 0), the rope is given an upward velocity π£(0) = βπ£0, where π£0 is a positive constant. Assume that point π does not reach the ground at any time in the problem.
a) Determine the net force (πΉπππ‘) acting on the rope in terms of π, π₯, π (ignore friction and the resistance of the rope to bending).
b) Find the speed of the rope π£(π₯) as a function of π₯ in terms of πΏ, π, π₯0.
c) Find π₯(π‘) in terms of π₯0, π, πΏ (hint: replace πΉπππ‘ in part (a) with ππ₯Μ ). Use the initial conditions provided to find the unknown constants.
d) Find the time when π₯(π‘) = 0.
e) Determine the minimum initial speed π£0 that allows the entire chain to climb on top of the table.
f) Show that if π£0 is πΌ times larger than the speed found in (e), then the time required for the entire
chain to climb on to the table is π‘ = 1/2 βπΏ/π ln (1+πΌ/πΌβ1)