A $90^{\circ}$ threaded elbow attached to the end of a 3 in. Sch. 40 pipe, and a reducer with an inside diameter of $1 \mathrm{in}$. is threaded into the elbow. If water is pumped through the pipe and out the reducer into the atmosphere at a rate of $500 \mathrm{gpm}$, calculate the forces exerted on the pipe at the point where the elbow is attached.