A nucleus, initially at rest, decays radioactively. In the process, it emits an electron horizontally to the east, with momentum 10.0×10-21 kg*m/s and a neutrino horizontally to the south, with momentum 5.0×10-21 kg*m/s.

(a) In what direction does the residual nucleus move (draw diagram, find angle )? 

(b) What is the magnitude of its momentum? 

(c) If the mass of the residual nucleus is 4.0×10-25 kg, what is its recoil velocity?