One of the ways that a magnet's domain could become unaligned is which of the following?

a. by using it too much
b. by putting it near a magnet that repels it
c. by breaking it in two
d. by dropping it

D. by dropping it.
I don't think using a magnet too much would do that.
If you put two magnets with their like poles together, you can feel a tension or force.  If you break it, then you just have two pieces of a magnet, but it still works.  So, dropping it seems like the most likely answer.  

Kinetic energy = 1/2mv^2. since the mass is constant we can form a ratio of it's kinetic energy at 60 divided by that at 30 to see ke(60)/ke(30) = +(60^2)/30^2). this may be said to 300% increase.