1. The problem statement, all variables and given/known data Essesntially me and my friend for our physics ISP (which is like a final project in ontario) are building this gravitational torsional balance: http://www.fourmilab.ch/gravitation/foobar/ Our set up is very similar, with our main balance arm being 30cm long , 5cm wide and 5cm high. The weights we are using are 50 ounces each (one on each side of the arm) and we are putting a 50kg weight 90 degress between each wight on the arm, 5cm off the radius. were trying to impress our physics teacher by showing him the theoretical value for how long the wieghts should take to attract gravitationally. 2. Relevant equations Both of our math skills are limited to differntial calculus and the little intergral ive tried to teach myself over the internet, i know that since acceleration is always changing it will involve integration of the acceleration function, and im guessing this displacemnt too, anyways i know this problem is exceptioanlly tough so any help would be much appreciated. 3. The attempt at a solution Honestly dont know where to start. Wrote f=Gmm(1/r^2) then subsituted expressions in for r and got stuck.