The heavier block in an Atwood machine has a mass twice that of the lighter one. The tension in the string is 16.0 N when the system is set into motion. Find the decrease in the gravitational potential energy during the first second after the system is released from rest.
I don't understand what the question is asking. Whose Gravitational potential energy is mentioned- 1st block or 2nd block?
When lighter block goes up it's gravitational Potential energy increases while that of heavier one decreases(since string is inextensible. So both will move same heights in same time.) so how can the system lose its Gravitational Potential energy?