• # question_answer A body of mass $2kg$ slides down with an acceleration of $3m/{{s}^{2}}$ on a rough inclined plane having a slope of $30{}^\circ$. The external force required to take the same body up the plane with the same acceleration will be:$(g=10m/{{s}^{2}})$[JEE Online 15-04-2018 (II)] A) $4N$ B) $14N$ C) $6N$ D) $20N$

 [d] Equation of motion when the mass slides down $Mg\sin \Theta -f=Ma$ $10-f=6$ $f=4N$ Equation of motion when the block is pushed up Let the external force be$F$ $F-Mg\sin \Theta -f=Ma$ $F-10-4=6$ $F=20N$