# Homework Help: Lunar Lander Formulas for Fuel / Masses

1. Apr 18, 2012

### dtturner12

1. The problem statement, all variables and given/known data

I am currently working on a computer science program which calculates the landing of a craft on a given planet. The user will enter in various known variables. I need some direction on what formulas to use for my program. I am strong in computer science however I haven't seen the formulas for this type of physics in a while and need some direction. Here is what variables the user will be able to "plug" into the equation to calculate the landing..

• The user initializes the program by entering the mass of the planet, mass of the craft, initial mass of fuel,fuel burn efficiency (amount of thrust/unit mass of fuel), initial height of craft above planet, and the initial velocity of the craft. This information will be entered from the keyboard.
• The height and velocity of the craft will only be in one direction orthogonal to a point on the planet.
• There are no other component forces acting upon the craft.
• Assume the planet and the craft are point masses.
• There are no other masses present.
• The program will prompt the user for amount of fuel to burn along with the burn time in seconds
• Appropriate calculations will be performed and the new craft vertical height above the planet and velocity will be displayed.
• A safe landing is when the craft contacts the surface of the planet within +/- 5m/s.
• Use the masses of the objects to calculate the force of attractio

2. Relevant equations

Relevant equations would be calculating the accelerations, and point masses

3. The attempt at a solution

i have a program written prompting all of the data from the keyboard however im not sure what to do with the data such as which formulas to use.