Question #3a5d4

1 Answer
Jun 8, 2015

Answer:

After correction from @stefan_zdre we got better agreement!!!
Thanks Stefan!

Explanation:

IF GPE is Gravitational Potential Energy and #d# is density in #(kg)/m^3#

You have from your formula that:
#GPE_(pyramid)=d*h^2*s^2*g/12=#
Where I think you refer to the expression fo r potential energy #U# as:
#U=mgh#
Where:
#mass=m=d*V# density times volume (#V=s^2h/3#)
And #h=# position of center of mass #=h/4#

With your data and #g=10 m/s^2#
I got:

#GPE_(pyramid)=2.57xx10^12 J#
#GPE_(Blocks)=1.33xx10^12#
#GPE_(Tot)=color(red)(3.9xx10^12) J#

Now if one man generates #160kJ# per day:
You have:
#160xx10^3*2845*23*365=color(red)(3.82xx10^12) J#