<Dd> F θ = a F A − b F B = 0 . (\ displaystyle F_ (\ theta) = aF_ (A) - bF_ (B) = 0. \, \!) </Dd> <P> Thus, the ratio of the output force F to the input force F is obtained as </P> <Dl> <Dd> M A = F B F A = a b, (\ displaystyle MA = (\ frac (F_ (B)) (F_ (A))) = (\ frac (a) (b)),) </Dd> </Dl> <Dd> M A = F B F A = a b, (\ displaystyle MA = (\ frac (F_ (B)) (F_ (A))) = (\ frac (a) (b)),) </Dd>

A lever is a bar that can pivot on a fixed point