Question

What is the angle at which the two nuclei fly apart if a nucleus at rest is all of a sudden splits into two small nuclei?

Answer 1

Very Nice Question. Thanks for asking it.

let M be the mass of nucleus.
Given that nucleus is at rest. 

Then the momentum of nucleus is zero before splitting up.[p=Mxv].

let m1 and m2 be the masses of two nucleus after splitting with velocities v1 and v2

 momentum after splitting=m1v1+m2v2

According to law of conservation of momentum:
m1v1+m2v2=0

m1v1=-m2v2
here negative sign indicates that the two nuclei parts will move in opposite direction to each other  and perpendicular to nucleus at rest before splitting.

Therefore angle between two nucleus parts after splitting is 180 degrees.

Answer 2

Answer:

180 degree is the answer