Kinematics Question 486

Question: A particle of mass m is moving in a circular path of constant radius r such that it’s centripetal acceleration ac it’s varying with time t as, ac=k2rt2 , The power delivered to the particle by the forces acting on it’s[IIT 1994]

Options:

A) 2πmk2r2t

B) mk2r2t

C) mk4r2t53

D) Zero

Show Answer

Answer:

Correct Answer: B

Solution:

Here the tangential acceleration also ex it’s which requires power.

Given that aC=k2rt2 and aC=v2r v2r=k2rt2

or v2=k2r2t2 or v=krt

Tangential acceleration a=dvdt=kr

Now force F=m×a=mkr

So power P=F×v=mkr×krt=mk2r2t



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