# Page:TolmanNon1.djvu/1

Non-Newtonian Mechanics :— The Direction of Force and Acceleration.

By Richard C. Tolman, Ph.D., Instructor in Physical Chemistry at the University of Michigan[1].

If force is defined as the rate of increase of momentum, the equation

 $\mathsf{F}=\frac{d}{dt}(m\mathsf{u})=m\frac{d\mathsf{u}}{dt}+\frac{dm}{dt}\mathsf{u}$ (1)

allows for a change in mass as well as a change in

1. Communicated by the Author.