sentence: Therefore we estimate the total number of bound myosin molecules along the filopodium to be N ≈ m· L. Because the force from a single myosin molecule is ∼ 2 – 3 pN ( Norstrom et al ., 2010 ) , the net force is F ≈ N ( 2 – 3 pN ) ≈ σ m , or σ ≈ L ( 2 – 3 pN ) .