Well in Back to the Future there was a ten minute period in time where there was two Marty's at once, (When Marty went 10 minutes back in time before he went to 1955, so there was he was watching his past self in Delorean) how would time fix itself and stop the infinite loop of there being two Marty's at once in that ten-minute gap. This isn't really a question for an assignment, I'm just curious.

(a) assume the equation x = at^3 + bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. determine the dimensions of the constants a and b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.) (b) determine the dimensions of the derivative dx/dt = 3at^2 + b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.)