ATAR Notes: Forum
VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE General & Further Mathematics => Topic started by: sandi on November 03, 2012, 11:28:36 pm
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During the holiday Bruce decides to go on a long drive up the highway, to no destination in particular. He gets in his car at home, Point O, and drives due north at a constant speed of 65km/h
ON the same day, Bruce's friend Sally also decides to go on a long drive on the same stretch of highway. Sally's house, point S, is 385 kms directly south of Bruce's home. Sally drives north at a constant speed of 100km/hr
Both Brue and Sally leave on their drives at exactly the same time.
QUESTION: Write a linear equation describing the distance Sally travels north, with respect to Bruce's home?
ANSWER: -385+100(hours)=Distance
Can anyone explain why it is negative 385 and not positive? I though it would be positive because Sally is moving towards Bruce's house....
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I think it considers north as positive and south as negative. It's initially 385km south and then travels 100km/h north.
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I think it assumes that Point O has coordinates (0,0) and therefore is Sally is 385 km away from that point in thesouth direction (assuming that the positive y values is north, and negative y values is south), then sally's house would be at point (0,385)