Which is an example of kinetic friction? friction between a car’s windshield and the air as you drive into the wind

friction between a sticky note and the page of a book as it marks your place

friction between your shoes and the ground when you stand still

friction between your skin and a pencil as it rests in your palm

friction between a car's windshield and the air as you drive into the wind.

Explanation: Hope this helps :)

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.

  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-