JEE Main 2019 — Laws Of Motion Question with Solution
From: JEE Main 2019 (Online) 10th January Evening Slot
Question
Two forces P and Q, of magnitude 2F and 3F, respectively, are at an angle with each other. If the force Q is doubled, then their resultant also gets doubled. Then, the angle is -
Choose an option
Show full solutionCorrect option: D
Correct answer
D120o
Step-by-step explanation
4F2 + 9F2 + 12F2 cos = R2
4F2 + 36F2 + 24F2 cos = 4R2
4F2 + 36F2 + 24F2 cos
= 4(13F2 + 12F2cos) = 52F2 + 48F2cos
cos = =
4F2 + 36F2 + 24F2 cos = 4R2
4F2 + 36F2 + 24F2 cos
= 4(13F2 + 12F2cos) = 52F2 + 48F2cos
cos = =
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This is a previous-year question from JEE Main 2019, covering the Laws Of Motion chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.