# Homework Help: Related rates

1. Aug 1, 2007

### rastakitty

1. A WWII sub sailing north spots a Japanese carrier directly above it sailing due east at 10 knots. If the submarine at the time of sighting the carrier is 5 miles away, has torpedoes that travel 40 knots/hr, it takes 3 mins to load and fire torpedo.
• At what angle with respect to original position of sighting must the submarine fire torpedo to strike the carrier. ?
• What is the travel time and distance traveled of the torpedo?

Also for the same data above show that taking the derivative of a trigonometric function can be used to yield the same results.

I started using Pythagoras, but got stuck,, this seems to be challenging to most of us who battled for hours.. if you can help I would be grateful.. this is a practice question to help me prepare for an exam..
Thank you

2. pythagorus and differentiation

3. I converted the time east (3mins) to distance, used pythag to get hyp,but that is only the distance before shooting the torpedo. not sure if i set the prob up correctly. but it is a real challenge. thanks if you can help...