Question

The resultant of two forces, one double the other is magnitude is perpendicular to the smaller of the two forces. The angle between the two forces is

Answer 1

Heya!!

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⇒Let the forces be F and 2F respectively.

Let R be the resultant.

Given that R is perpendicular to F.

Therefore,

⇒R²+F²=4F²
⇒R²=3F²
⇒R²=F²+4F²+2(F)(2F)cosФ
⇒3F²=5F²+4F²cosФ
⇒-2F²=4F²cosФ
⇒cosФ=-2F²/4F²
⇒cosФ=-1/2

⇒Ф=120°

Hope this helps you ☺☺