Question

An object of mass 40 kg is raised to a height of 5 metre above the ground. what is its potential energy? if the object is allowed to fall, find its kinetic energy when it is half -
way down.

Answer 1

mass of the object is equal to 40 kg
height above the ground of the object is equal to 5 m
acceleration due to gravity or g is equal to 9.8 m/s^2

so its potential energy is equal to the product of mass in and acceleration due to gravity and height above the ground
P.E. = 40× 9.8× 5 J
= 1960 J
height of the object when it is Halfway down is equal to total height divided by 2 which is is equal to 5 m / 2 is equal to 2.5 m
its initial velocity is equal to zero metres per second
by applying the equation of motion
v^2= 0+ 19.6× 2.5
v^2= 49
so its K.E. when it is Halfway down
=1/2× 40× 49 J
= 980 J

Answer 2

_/\_Hello mate__here is your answer--

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Given:-

m = 40 kg

g = 9.8 m/s^2

h = 5 m

We know that,

potential energy = mgh

= 40 × 9.8 × 5 J

= 1960 J

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♦♦The total mechanical energy (Kinetic and potential energy) of an object remains constant. (law of conservation of energy)

Therefore, when the object is half-way down, its potential energy become half the original energy and remaining half converted into kinetic energy.

Hence, the kinetic energy = ½ (1960) J = 980 J

I hope, this will help you.☺

Thank you______❤

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