A) \[2v\text{ }cos\text{ }50{}^\circ \]
B) \[2v\text{ }sin\text{ }50{}^\circ \]
C) \[2v\text{ }cos25{}^\circ \]
D) \[2v\,\sin \,25{}^\circ \]
Correct Answer: D
Solution :
\[\Delta v=\sqrt{{{v}^{2}}+{{v}^{2}}-2vv\,\cos {{50}^{o}}}\] \[=\sqrt{2}v{{(1-\cos {{45}^{o}})}^{1/2}}\] \[=\sqrt{2}v{{(1-\cos 2\times {{25}^{o}})}^{1/2}}\] \[=\sqrt{2}v{{[1-(1-2{{\sin }^{2}}{{25}^{o}})]}^{1/2}}\] \[=\sqrt{2}v\times \sqrt{2}\sin {{25}^{o}}\] \[=2v\sin {{25}^{o}}\]
You need to login to perform this action.
You will be redirected in
3 sec
