1. The problem statement, all variables and given/known data An asteriod hits the Moon and ejects a large rock from its surface. The rock has enough speed to travel to a point between the earth and the moon where the gravitational forces on it from the earth and the moon are equal and opposite in direction. At that point the rock has a very small velocity toward Eart. What is the speed of the rock when it encounters Earth's atmosphere at an altitude of 700 Km above the surface? 2. Relevant equations Gravitational potential energy: PE= -Gm1m2/r Conservation of Mechanical Energy: KE(intial)+PE(intial)=KE(final)+PE(final) 3. The attempt at a solution well firstly ididnt get what they mean that its moving towrds earth, I mean if the forces between the moon and earth are equal and opposite in direction shouldn't the velocity of the rock be zero, Ijust need calrification here becuase that was confusing me a bit. And also I tired finding the velocity that it moves with toward earth but I dont know anything about the distance that it travelled. I just basically need someone to clarify this problem for me thats all and thankyou:).