In Fig. $26-37,$ a resistance coil, wired to an external battery, is placed inside a thermally insulated cylinder fitted with a frictionless piston and containing an ideal gas. A current $i=240 mathrm{mA}$ flows through the coil, which has a resistance $R=550 Omega$ . At what speed $v$ must the piston, of mass $m=12$ kg, move upward in order that the temperature of the gas remains unchanged?