At time $t$, in hours, a lake is covered with ice of thickness $y$ cm, where $y=0.3 t^{1.6}$.

1. How fast is the ice forming when $t=1$? When $t=2$? Give units.
when $t=1$:
when $t=2$:

2. If ice forms for $0\leq t \leq 3$, at what time in this interval is the ice thickest? At what time is the ice forming fastest? (Give units here, too.)
Ice is thickest at $t =$
Ice is forming fastest at $t =$