# About my thinking Kenetic E

About my thinking !! Kenetic E"

last week i am thinking about the kenetic energy of the earth compared with the object that falling down .

I assume that it may be equal to 0 or ∞ but no why ??

How about you for this case ?

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Doc Al
Mentor

Not sure what you are asking about or why you'd compare the kinetic energy of the earth (in what frame?) to the kinetic energy of a falling object.

Ohh sorry !

Hmm , i have ever seen comparison of the K.E of object 1 to K.E of object 2 while falling down . So in this case , i want to compared with the earth instead of object 2.

thanks for answer , just doubt !

Doc Al
Mentor

Hmm , i have ever seen comparison of the K.E of object 1 to K.E of object 2 while falling down . So in this case , i want to compared with the earth instead of object 2.
I'm still not understanding what you want to do. Usually, one measures the speed of the falling body--and thus its kinetic energy--with respect to the ground. What do you propose instead?

i assume that the object's mass is m Kg. and the earth's mass is M Kg.
i want to know the kenetic of object respect to the earth's while the object is falling .

it may be m/M or M/m or equal to 1 or 0 .

i try to understand to law of kenetic energy but it so hard of this case for me.
thanks for pay attention to my doubt.

the kinetic energy of the falling object is constantly changing because its velocity is changing due to the acceleration due to gravity. You must specify at what location/time you want to know the object's kinetic energy.