The brake power (B.P.) of the engine is given by (where W = Brake load or dead load in newtons, l = Length of arm in meters, N = Speed of engine in r.p.m., S = Spring balance reading in newtons, D = Dia. of brake drum in meters, and d = Dia. of rope in meters)

• A. B.P = (Wl ‚àö√≥ 2≈ì√ÑN)/60 watts
• B. B.P = [(W - S) ≈ì√ÑDN]/60 watts
• C. B.P = [(W - S) ≈ì√Ñ (D + d) N]/60 watts
• D. All of these