Answer: Choice D) 19.6 J
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Work Shown:
m = 2 kg = mass
g = 9.8 m/s^2 = acceleration of gravity (approximate)
h = 1 m = height
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PE = potential energy
PE = m*g*h
PE = 2*9.8*1
PE = 19.6 J
The vase has approximately 19.6 Joules of potential energy.
We didn't have to make any conversions because the unit Joule is equivalent to the more complicated unit of kg*m^2/s^2 so it only involves kilograms, meters and seconds. If however the mass was given in say grams (instead of kg), then you'd need to convert to kg.