JEE Main 2018PhysicsWork Power EnergyHardMCQ

JEE Main 2018 — Work Power Energy Question with Solution

JEE Main 2018 (16 Apr Online)

Question

A body of mass m starts moving from rest along x-axis so that its velocity varies as v=as where a is a constant and s is the distance covered by the body. The total work done by all the forces acting on the body in the first t second after the start of the motion is

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Show full solutionCorrect option: D
Correct answer
D18ma4t2

Step-by-step explanation

v=as=dsdt

⇒dss=a.dt

⇒2s=at

⇒s=a2t24, v=dsdt=a2t2

⇒Wall=∆K=Kf-Ki

⇒Wall=12mv22-v12

⇒v1=0, v2=a2t2

⇒Wall=12ma2t22-0

⇒Wall=18ma4t2

⇒Wall=∆K

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About this question

This is a previous-year question from JEE Main 2018, covering the Work Power Energy 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.