Good night guys. I've been studying for a test on mechanical vibrations and I came across this problem of a telescopic crane (or whatever its name is). It's necessary to obtain a equivalent constant kp and then it has to be decomposed into its vertical component and the author uses a squared cosine of 45 degrees to do so. I would have used a sine of 45 degrees instead without squaring it. I know the sine and the cosine have both the same result, I'm just using a sine because the vertical component is needed.(adsbygoogle = window.adsbygoogle || []).push({});

Could you please tell me why the author is using a squared cosine? Also, why is the force pulling and not pushing when the weight of the guy is obviously going downwards?

Thank you

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# Why is this rigidity constant decomposed using a squared cosine?

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