A four-stroke single cylinder petrol engine has a bore of \(150 \mathrm{~mm}\) and stroke of \(250 \mathrm{~mm}\). At \(500 \mathrm{rpm}\) and full load, the net load on friction brake is \(435 \mathrm{~N}\) and torque arm is \(0.45 \mathrm{~m}\). The indicator diagram gives a net area of \(580 \mathrm{~mm}^{2}\) and a length of \(70 \mathrm{~mm}\) with a spring rating of \(0.85 \mathrm{bar} / \mathrm{mm}^{2}\). Determine: (i) indicated power, (ii) brake power, and (iii) mechanical efficiency.