Awater molecule is made up of one oxygen and teo hydrogen atoms. why is water considered a pure substance

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.

photocells convert light energy to electricity

where are the vectors ?

the maxium height is 34m/s