the question is as given above.   no more doubts please.

i want the solution.

yes the plank is frictionless.

please any one , give the solution to my question.

A cylinder of mass m is kept on the edge of a plank of mass 2m and length 12m, which in turn is kept on smooth ground.coefficient of friction between the plank and the cylinder is 0.1. The cylinder is given an impulse , which imparts it a velocity 7m/s but no angular velocity.Find the time after which the cylinder falls off the plank.