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Question: Answered & Verified by Expert
Two equal forces ( $p$ each) act at a point inclined to each other at an angle of $120^{\circ}$. The magnitude of their resultant is
PhysicsMathematics in PhysicsCOMEDKCOMEDK 2019
Options:
  • A $p$
  • B $2 p$
  • C $p / 2$
  • D $p / 4$
Solution:
1906 Upvotes Verified Answer
The correct answer is: $p$
The magnitude of the resultant force can be given by parallelogram's law of vector addition i.e.,
$$
\begin{aligned}
\Rightarrow \quad F_{\text {net }} &=\sqrt{2 p^{2}+2 p^{2} \times \cos \left(120^{\circ}\right)}\left(\because \theta=120^{\circ}\right) \\
&=\sqrt{2 p^{2}+2 p^{2}\left(-\frac{1}{2}\right)} \\
&=\sqrt{p^{2}} \\
&=p
\end{aligned}
$$

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