okay, here's the problem. A rocket falls from rest a 945m with an initial velocity of zero. Suppose there is still fuel in the rocket, and at what height should the engines be fired again to brake the rocket's fall and allow a perfectly soft landing? Acceleration of the rocket engines is +29.4 m/s^2. so basically I want to know when should the rocket engines be fired so the velocity can be decreased to zero by the time the it hits the ground. I don't know where to start.