Find the Velocity - a Vector Problem
Date: 09/25/2002 at 20:40:54 From: Danbi Subject: Physics A river flows westward at 8 m/s. A person wants to go directly across the river so that the resultant velocity is 12 m/s northward. Find the velocity of the motorboat that would be required to achieve this resultant velocity. This is a question my Physics teacher posed to the class for our homework assignment. I'm not sure on how to go about solving it. Any help would be much appreciated.
Date: 09/26/2002 at 16:52:21 From: Doctor Jeremiah Subject: Re: Physics Hi Danbi, Its a vector problem. You can't go straight north in a boat with a current pushing you west. You must go northeast. The east component of the velocity must be the same as the current's velocity in order to cancel it out and end up with a straight north direction. The velocity of the boat would look like this: ^ | | | | | 12 | | | | | +----8----> So combine these velocities into a single vector and find its magnitude. The magnitude of the combined vector is the speed that the boat must make in the northeast direction. Let me know if you have more questions. - Doctor Jeremiah, The Math Forum http://mathforum.org/dr.math/
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