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Grade 12th passMechanics

Magnitude of 2forces when acting at right angles provide a resultant of 20and when acting at 60prduce a resultant equal to 28.fond magnitude of 2forces.

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Profile image of Hasna ansar
5 Years agoGrade 12th pass
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1 Answer

Profile image of Harshit Singh
5 Years ago
Dear Student

Let the two forces be x and y and the resultant be r
when both are at 90 degrees
r2 = x2 + y2
x2+ y2= 202 = 400 …...(i)

Now when both are at 60 degrees

r2 = x2 + y2 + 2xycos60
282 = 784 = x2 + y2 + xy
784 = 400 + xy

xy = 384

(x+y)2 = x2 + y2 + 2xy
(x+y)2= 400 + 2(384)
(x+y)2= 1168
x+ y = 34.17

Similarly
x-y =(√-368

there is negative sign inside square root

Please check the question again

Thanks