A block starting from rest slides down a frictionless inclined plane of length. What is the distance when the block reaches 1/2 of the final speed?
a) ( /{1}/{4} ) times the length of the incline
b) ( /{1}/{2} ) times the length of the incline
c) ( /{3}/{4} ) times the length of the incline
d) The full length of the incline