1. The problem statement, all variables and given/known data On a planet far, far away, an astronaut picks up a rock. The rock has a mass of 4.40 kg, and on this particular planet its weight is 40.0 N. If the astronaut exerts an upward force of 49.5 N on the rock, what is its acceleration? Magnitude _____m/s2 Direction up down 2. Relevant equations Acceleration = Velocity/Time 3. The attempt at a solution I know that the rock is moving in the upward direction, because the force applied to the rock is more than its mass. One thing that I do not understand however, is how to find the acceleration. I am given the velocity, 49.5 but I do not get the time. How can I figure out the time knowing that the velocity is 49.5 and the rock weighs 40 N?