3. (20 pts.) Consider the arrangement of the five particles pictured below with a = 3.0 m and \theta = 20°. Suppose that the five particles all have the same mass m = 12 kg.
a) What is the gravitational force exerted by particle 3 on particle 1?
Please provide the vector $\vec{F}_{13}$.
b) What is the net gravitational force exerted by particles 2, 3, 4, and 5 on particle 1?
Please provide the vector $\vec{F}_{1, net}$
c) Ignoring particles 3, 4, and 5, please calculate the gravitational potential energy
between particles 1 and 2.