Question about radioactive decay

[cpspolly]

Homework Statement

Please help with these questions, really don't know how to do it:)
thanks a lot

Relevant Equations

maybe related to conservation of momentum

 

[haruspex]

Homework Statement:: Please help with these questions, really don't know how to do it:)
thanks a lot
Relevant Equations:: maybe related to conservation of momentum

View attachment 299171

Per forum rules, you must post an attempt. Urgency is not an excuse, and failure to post an attempt straight away is only going to slow things down.
Yes, momentum conservation will be a good start, so write the appropriate equation. Any other conservation laws that might apply?