1. The problem statement, all variables and given/known data A 10-m-long glider with a mass of 680 kg (including passengers) is gliding horizontally through the air at 30 m/s when a 60 kg skydriver drops out by releasing his grip on the glider. What is the glider's velocity just after the skydiver lets go? 2. Relevant equations Pi= Pf m1v1= m2v2 3. The attempt at a solution m1v1=m2v2 (680)(30)= (680-60)v2 v2= 32.9 m/s Glider's velocity just after the skydiver lets go is 32.9 m/s. This is how I solved the question. however, for the concept of conservation of momentum, it has to be an isolated system right. So when one skydiver lets go, do we ignore the force of gravity on the skydiver? This question seems too easy this way but I can't seem to relate it to the concept of the isolated system. Thanks in advance!