On a smooth horizontal floor, an object slides into a spring which is attached to another mass that is initially stationary. When the spring is most compressed, both objects are moving at the same speed. Ignoring friction, what is conserved during this interaction?
A) momentum and potential energy
B) kinetic energy only
C) momentum and kinetic energy
D) momentum onlyE) momentum and mechanical energy

(E) Momentum and mechanical energy

Explanation:

 The momentum and the mechanical energy is basically conserved during the given interaction process as the forces on the given system are in the form of internal nature and then the momentum are get conserved.

According to the given question, on the smooth floor when an object are slides by using the spring then the momentum and the mechanical energy are conserved.

The mechanical energy is the combination of both the kinetic and the potential energy that is used for doing some amount of work. Therefore, Option (E) is correct answer.  

tube or goog with be a great resource to with that question

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge