Question

an object of mass 40 kg is raised to a ground. what is the potential energy? If the object is allowed to fall, find its kinetic energy when it is half way down
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Answer 1

$\huge\green{\star ANSWER \star}$

Mass of the object, M=40kg

Height up to which it is raised

h=5 m

Potential energy P.E=Mgh

P.E=40×10×5=2000J

Let its kinetic energy be Ek when it is halfway down i.e h′=h/2

According to the conservation of energy,

K.Ei+P.Ei=K.Ef+P.Ef

0+2000=Ek+Mgh/2

∴ 2000=Ek+40×10×5/2

⟹Ek=1000J