# Tag Info

In a massless string the sum of forces acting on every part of the string must be zero, otherwise, if the force was finite, the string would get an infinite accelleration $a = \lim_{m\rightarrow 0} F/m = \infty$. (The more physical way to say it is that if the mass is very small the force must be very small for finite accelerations). So in frictionless and ...