Friday, September 23, 2011

How do you find the direction and magnitude of the resultant force, that is, how do you find F1 F2?

Two forces, F1, of magnitude 60 newtons (N) and F2 of magnitude 70 newtons, act on an object at angles of 40 degrees and 130 degrees (respectively) with the positive x-axis. Find the direction and magnitude of the resultant force, that is, find F1+F2. Round the direction and magnitude to two decimal places.





How do I do this? This is the only problem on my precalc study guide that I do not get. Please help!|||They make a 90潞 angle (130 - 40) with each other which makes the magnitude just be the hypotenuse of a right triangle with legs 60 and 70 so use Pythagorean (or cosine law if you must)





r = 鈭?60虏 + 70虏) 鈮?92.20 N





Now use that to get the angle. Find the angle n between the 60 and this resultant by SOH CAH TOA (or sine law if you must)





cos n = 60/92.20


inverse cos says that n 鈮?49.40 潞 so add that to 40潞

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