3. A stone is dropped into a deep well and is heard to hit the water 3.41 s after Determine the depth of the well.
4. Find the angle between the following two vectors using the dot product.
u= 3, 4, 7>: V=<-2, 3, -5>
5. Find the angle between the following two vectors using the cross vector pro
u=<3, 4, 7>: v=< -2,3, -5>

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.

a.   mass number from atomic number