Question

A body can reach maximum height h when it is projected vertically up.The ratio of potential energy to kinetic energy at 4h/5 is

Answer 1

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Let the point from where the stone is projected be A. Let the point where the stone attains the maximum height 'h' be C. Let the point which is at a height of 3h/4 from the feline be B. Let the mass of stone be 'm'

Now,

PEat point C =mgh

KEat point C =0

So, Total mechanical energy=PEC + KEC=mgh

Since the only force acting on the stone is gravitational force which is a conserved force so the total mechanical energy at every point in the system will always be constant.

So,

TMEB=PEB+KEB

mgh  =3mgh/4+KEB

KEB =mgh/4

Now,

KEB:PEB=mgh/4:3mgh/4

KEB:PEB=1:3

ANS:-1:3



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