THERE ARE TWO MOTION : for the upside motion - F= MG +KV^2 Mdv/dt = MG + KV^2 Mdv/ds . ds/dt=Mg + KV^2 Mv /(Mg KV^2) dv = ds [v0 ][o ] MV/(MG +KV^2). dv = [ 0][l ] ds (try the integration if your maths is strong and you'll get -) M[ ln (MG/(MG + KVo^2) )]/2k = L ( L is the max height attained ) ............1 now for downward motion m dv/dt = MG - KV^2 mV / (mg - kv^2) dv = ds integrate both side [o ][v' ] mV/( mg - kv^2) = [0 ][L] ds again try and you'll get m[ ln ( | mg - kv'^2 |/mg ] / 2k = L .......................2 compare 1 and 2 ln (mg / (mg + KV^2) ) = ln (mg -kv^2 /mg)
v' = [ MGKV0^2 / ( MGK + K^2 V0^2) ]
V' = V0/ (1+ KV0^2 /MG ) V' is your answer definetely ... write if you can't understand my solution i might elaborate it further .
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