Answer:
c must have units of distance/time^2
Step-by-step explanation:
Since y must be in units of distance, then all the terms that add up to give "y" must all have units of distance. That means that also the last term c * t^2 has units of distance, and therefore, if the product of c times t^2 produces a distance, then c must have units of distance divided the square of time units, so when multiplied by t^2 the time units in denominator and numerator cancel out.