The sum of two forces P → and Q → is R → such that R → = P → . Find the angle…

The sum of two forces P→ and Q→ is R→ such that R→=P→. Find the angle between resultant of 2P→ and Q→ and Q→ , ________

Solution


So angle between 2P→+Q→ and Q→ is 90o


Alternate solution


P→+Q→=P→
P2+Q2+2PQcos⁡θ=P2
⇒Q+2PQcos⁡θ=O
⇒cos⁡θ=-Q2P

tan⁡α=2Psin⁡θ2Pcos⁡θ+Q=∞
∵2Pcos⁡θ+Q=0
α=90o

Asked in: JEE Main 2020 (07 Jan Shift 2)

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