A particle is released from height S from the surface of the Earth. At a certain height its kinetic energy…

A particle is released from height S from the surface of the Earth. At a certain height its kinetic energy is three times its potential energy. The height from the surface of the earth and the speed of the particle at that instant are respectively___
  1. S4,3gS2
  2. S4,3gS2
  3. S4,3gS2
  4. S2,3gS2

Solution

At Every pt.

KE+PE= constant

so,

(KE)A+(PE)A=(KE)B+(PE)B

0+mgS=3(PE)B+(PE)B

mgS=4mgh

h=S4

Now,

KE at p t . B-

At p t . B-

KE=3PE

12mv2=3mgs4

v=32gS

Asked in: NEET 2021

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