A) \[\theta ={{\cos }^{-1}}\left( \frac{P-Q}{Q} \right),\,\,R=\sqrt{{{P}^{2}}-{{Q}^{2}}+2PQ}\]
B) \[\theta ={{\cos }^{-1}}\left( \frac{Q-P}{Q} \right),\,\,R=\sqrt{{{Q}^{2}}-{{P}^{2}}+2PQ}\]
C) \[\theta ={{\cos }^{-1}}\left( \frac{P-Q}{P} \right),\,\,R=\sqrt{2{{P}^{2}}-{{Q}^{2}}+2PQ}\]
D) None of the above
Correct Answer: B
Solution :
Let \[\theta \] be the angle between the forces \[P\] and \[Q\], then \[{{R}^{2}}={{P}^{2}}+{{Q}^{2}}+2PQ\cos \theta \] ... (i) Let the resultant \[R\] make an angle \[\alpha \] with the direction of force \[P\] and \[\beta \] with the direction of force\[Q\]. Then,You need to login to perform this action.
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