1.

Two vectors acting through a point are in the ratio `3 : 5`. If the angle between them is `60^(@)` and the magnitude of their resultant is `35` , find the magnitude of vectors.A. `12 N , 20 N`B. `15 N , 25 N`C. `18 N , 30 N`D. `21 N , 28 N`

Answer» Correct Answer - B
`P = 3x , Q = 5x , theta = 60^(@) , R = 35`
`R^(2) = P^(2) + Q^(2) + 2 P cos theta`
`(35)^(2) = (3x)^(2) + (5x)^(2) + 2 . 3x . 5x . Cos theta 60^(@)`
`= 9x^(2) + 25 x^(2) + 15 x^(2) = 49 x^(2)`
`35 xx 35 = 7 xx 7 x^(2)`
`x = 5`
`P = 3x = 15 N , Q = 5x = 25 N`


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