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

At a certain instant, the earth, the moon, and a stationary 1030kg spacecraft lie at the vertices of an equilateral triangle whose sides are 3.84×10^5km in length.

Find the magnitude of the net gravitational force exerted on the spacecraft by the earth and moon.

**2. Relevant equations**

GMm/r^2 = Fg

r = 3.84*10^5 km

Me = 5.98*10^24 kg

Mm = 7.35*10^22 kg

G = 6.67*10^-11

Ms = 1030kg

**3. The attempt at a solution**

http://ift.tt/1g0yY6s

I think it’s probably a simple error somewhere but I’ve gotten about 3-4 different answers all which are not F=2.8N – I’ve tried calculating it at different stages in the algebra – are the angles somehow not based off 60*? I don’t know what it’s missing.

http://ift.tt/1eSSahg