a=(F/m)*v^n

where a is the rectilinear acceleration of the mass m or spacecraft, F is the thrust force of the motors in same

direction

as a and, velocity v of mass m in same direction as a. The exponent n seems not be a constant, it increases

with

F/m and perhaps increases with v. For F/m=100 newtons/kilogram, the n=1/2; for F/m=1newton/kilogram, the

n=1/100; and for F/m= 10 newtons/kilogram, the n=1/3. When n becomes greater than 1, the acceleration a

may become

negative and the spacecraft may travel backwards

in time. This still has to be tested using electrons as the mass m