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yrelhan4
The end of uniform rope of mass 'M' and length 'L' that is piled on a platform is lifted with a constant velocity 'v' by a variable force F . Find the value of force 'F' as lifted postion of 'x' .
Hint: Start by using this definition of force. Force is the time rate of change of momentum i.e.\[F=dP/dt=d(mv)/dt=vdm/dt+mdv/dt\] the mass the force is lifting is changing. the mass at any given instant is \[m=\frac{ M }{ L }x\] where x is the length of rope lifted. We also know \[x=vt\] substitute and solve.