Yucky Calculus stuff - please help

Okay, I have 2 questions that I can't figure out...I've manipulated them in so many ways, but it just doesn't seem like i'm doing it right, can someone please show me how they should be answered.

1. Frank and Gordon have decided to go on seperate vacations. At 9am this morning Gordon's plane was exactly 300km south of Frank's plane. Frank's plane was flying west at the rate of 650 km/h and Gordon's plane is flying north at a rate of 525km/h

a. At what rate is the distance between Frank and Gordon changing at 9:15am?

b. When do Frank and Gordon's planes cease to approach one another?

2. After his vacation, Gordon decided he needed to get into shape. Frank agreed to build him a 400m track in the shape of two semi-circles at the ends of a rectangle. The straight sections of the track must be at least 100m in length, and the radius of the semi-circle must be at least 20m. Find the dimensions of the track that enclose the maximum area and the minimum area.