JEE Main 2020PhysicsMotion In Two DimensionsEasyMCQ

JEE Main 2020 — Motion In Two Dimensions Question with Solution

JEE Main 2020 (08 Jan Shift 2)

Question

A particle moves such that its position vector r→t=cos⁡ωti^+sin⁡ωtj^ where ω is a constant and t is time. Then which of the following statements is true for the velocity v→t and acceleration a→t of the particle:

Choose an option

Show full solutionCorrect option: D
Correct answer
Dv→ is perpendicular to r→ and a→ is directed towards the origin

Step-by-step explanation

r→=cos⁡ωti^+sin⁡ωtj^
v→=dr→dt=ω-sin⁡ωti^+cos⁡ωtj^
a→=dv→dt=-ω2cos⁡ωti^+sin⁡ωtj^
a→=-ω2r→∴a→ is antiparallel to r→
v→.r→=ω-sin⁡ωtcos⁡ωt+cos⁡ωtsin⁡ωt=0
So v→⊥r→

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About this question

This is a previous-year question from JEE Main 2020, covering the Motion In Two Dimensions 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.