Consider a screw dislocation in a single crystal of FCC Cu that is gliding on the (-1 -1 1) slip plane with a Burgers vector of b=a/2[101]. a) Draw a unit cell for FCC Cu and indicate the burgers vector of this perfect dislocation and the two Shockley partial dislocations that it can dissociate into. b) Give the magnitude and direction of the perfect dislocation and the Shockley partials. c) If this dislocation were to cross slip from the (-1 -1 1) plane to the (1-1-1) plane, what would the Shockley partials in the new plane be?