Patel108 Posted March 7, 2011 Report Share Posted March 7, 2011 1. Yacht A moves according to x(t) = 4 + t, y(t) = 5-2t where the distance units are kilometres and the time units are hours. yacht B moves according to x(t) = 1 + 2t, y(t) = -8 + t, t is greater than or equal to 0.If they start at 6:00 am, find the time when the yachts are closest to each other.2. Submarine P is at (-5, 4) and fires a torpedo with velocity vector (3 -1) at 1:34 pm. Submarine Q is at (15, 7) and a minutes later fires a torpedo in the direction (-4 -3). Distances are measured in kilometres and time is in minutes.Q's torpedo is successful in knocking out P's torpedo. At what time did Q fire its torpedo and at what time did the explosion occur?Thanks to whoever helps me!! Reply Link to post Share on other sites More sharing options...
Keel Posted March 7, 2011 Report Share Posted March 7, 2011 1. Yacht A moves according to x(t) = 4 + t, y(t) = 5-2t where the distance units are kilometres and the time units are hours. yacht B moves according to x(t) = 1 + 2t, y(t) = -8 + t, t is greater than or equal to 0.If they start at 6:00 am, find the time when the yachts are closest to each other.2. Submarine P is at (-5, 4) and fires a torpedo with velocity vector (3 -1) at 1:34 pm. Submarine Q is at (15, 7) and a minutes later fires a torpedo in the direction (-4 -3). Distances are measured in kilometres and time is in minutes.Q's torpedo is successful in knocking out P's torpedo. At what time did Q fire its torpedo and at what time did the explosion occur?Thanks to whoever helps me!!I'm not sure if I'm right, can someone check? I also cheated with question 1 and used my GDC, would you really have to differentiate or have I got it all wrong? (sorry for the messy handwriting...I am male ) 2 Reply Link to post Share on other sites More sharing options...
Patel108 Posted March 8, 2011 Author Report Share Posted March 8, 2011 THANK YOU SO MUCH!!!!!!!! You're a lifesaver!By the way, why exactly do you have to do A - B to find when the yachts are closest to each other?Thank you again! Reply Link to post Share on other sites More sharing options...
Keel Posted March 8, 2011 Report Share Posted March 8, 2011 THANK YOU SO MUCH!!!!!!!! You're a lifesaver!By the way, why exactly do you have to do A - B to find when the yachts are closest to each other?Thank you again!You are welcome,Well obviously if the two lines are not parrell they will intersect. You have to remember that there is the factor of time involved. A-B represents the distance between the two yachts in relation to time. Although the routes of the two yachts cross, they never meet. So once you find A-B, you differenciate to fine the min. distance between the two yachts for a particular time and that time will be when they are at min distance. Reply Link to post Share on other sites More sharing options...
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