A 20 kilogram object strikes the ground with 1830 Joules of kinetic energy after falling freely from rest. How much potential energy did the object have as it began to fall?

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.

d is the correct answer