How would you calculate the force of gravity on a 19 #kg# mass at Earth's surface, assuming the mass of Earth is #6.10^24# #kg#, and its radius is #6.410^6# #m#?

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Answer 1 · 2015-10-30T19:13:40

Have a look:

You could use Newton's Law of Universal Gravitation:
#F=G(mM)/r^2#
where:
#M# mass of the Earth
#r# radius of Earth
#G# Universal Grav. Constant.

BUT

you know that on Earth's surface
#GM/r^2=g=9.81m/s^2# acceleration of gravity;
so you have that:
#F=mg=19*9.81=186.4N# that normally we call Weight.

How would you calculate the force of gravity on a 19 #kg# mass at Earth's surface, assuming the mass of Earth is #6.*10^24# #kg#, and its radius is #6.4*10^6# #m#?