Power Smithen
Work Energy-
A pulley system conisisting of three pulleys is used to lift a pallet
of
bricks Weighing 600N
through a height of 40m. The
force required to lift the pallet
at a
steady speed is 210N and the rope is pulled through a distance of 120m

(a) Neglecting
the mass
of the pulleys and rope, calculate the useful work
done in lifting the pallet. ​

how to make a simple air condition

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.