A submarine was situated 800 feet below sea level. If it ascends 250 feet, what is its new position?

1 Answer
May 16, 2018

See below

Explanation:

Let's take sea level as our horizon: if you are on the water surface, your height is #h=0#. Also, let's assume a vertical axis pointing upwards. This means that the submarine, being #800# feet away from the horizon in the opposite direction with respect to the axis, will have a negative height of #h_0=-800#.

If it ascends #250# feets, it gains altitude, so the new height is #h_1 = -800+250 = -550# feet.

Note that this problem heavily depends on the coordinate system you adopt. In fact, I may have chosen an axes whose origin is set at the initial position of the submarine (which would have become the #h_0=0#), pointing upwards, and the new position would have been #h_1 = 0+250=250# feet.

The only things that won't change is that the new position will be #250# "more" than the old one. But if you want to compute absolute values, you need to specify a coordinate system, otherwise you may have as many answers as you want.