Question $2$:

The indicated power developed by an engine with compression ratio of $8,$ is calculated using an air$-$standard Otto cycle $($constant properties$).$ The rate of heat addition is $10$ kW$.$ The ratio of specific heats at constant pressure and constant volume is $1\mathrm{.}4.$ The mechanical efficiency of the engine is $80\%.$ The brake power output of the engine is $\_\_?$