JEE Main 2021PhysicsLaws of MotionHardNumerical

JEE Main 2021 — Laws of Motion Question with Solution

JEE Main 2021 (31 Aug Shift 1)

Question

A car is moving on a plane inclined at 30° to the horizontal with an acceleration of 10 m s-2 parallel to the plane upward. A bob is suspended by a string from the roof of the car. The angle in degrees which the string makes with the vertical is (Take g=10 m s-2)

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Show full solutionCorrect answer: 30
Correct answer
30

Step-by-step explanation

First, make the free body diagram, of an inclined plane with acceleration in an inclined plane moving in an upward direction.


With respect to the car, the F.B.D. is as follows at equilibrium, T is equal and opposite to the resultant of a1 ​ and a2 ​ As a1+a2 ​ makes 30°with vertical; T and,  the string is also making 30° with vertical. 

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About this question

This is a previous-year question from JEE Main 2021, 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.