Problem 3: Assume that you are aboard a research submarine doing submerged training exercises in the Atlantic Ocean. At time t = 0, you start porpoising (going alternately deeper and shallower). At time t = 4 min you
are at your deepest, y =- 1000 m. At time t = 4 min you next reach your shallowest. y =- 2000 m. Assume
that y varies sinusoidally with time.

A. Sketch the graph of y versus t

B. Write an equation expressing y as a function of t

C. Your submarine can’t communicate with ships on the surface when it’s deeper than -300m. At time t=0, could your submarine communicate with a ship? How did you arrive at your answer?

D. Between what two nonnegative times is your submarine first unable to communicate with a ship?