# A body of mass 4kg is thrown up with a speed of 30m/s calculate K.E of body and P.E at top .

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The Brainliest Answer!

When A body is thrown up with some velocity(V m/s) This body(m) looses it's K.E.as it go up it's velocity vanishes and gains the P.E.,Hence at the top K.E of the body will fully converted into the P.E.

If E₁ = Initial energy =

and E₂ = Final energy of the body

And, Initial K.E = 1/2(mv²) = 1/2(4×30²) = 1800 J

Final K.E or K.E at the top is Zero as it's velocity is zero at the top.

A/c to energy conservation,

E₁ = E₂

Initial K.E + Initial P.E = Final K.E + Final P.E

or, 1/2(mv²) + 0 = 0 + Final P.E

Final P.E = 1/2(4×30²)

Therefore P.E at the top = 1800 J

And K.E at the top is Zero

=1/2*4*900

=1800J

=1.8KJ

P.E=MgH

=4*10*45 (H can be calculated by III equation of motion)

=1800J

=1.8KJ