Assuming smooth surfaces, find the reactions induced at all contact surfaces.

Since there are many unknowns, we can not solve the sum by using one F.B.D. Since the system is in equilibrium, we can break it as shown below:-

Applying static conditions of equilibrium,

$∴ ΣM_C \cong 0 ( +ve) \\ ∴ R_3 × r+500 \cos30 ×r+500 \sin30 ×r+ R_5×r=0 \\ ∴ R_3×r=500 \cos30 +500 \sin30 + R_5 \\ ∴Σ F_x (→ +ve)=0 \\ ∴R_5+500 \sin30=0 \\ ∴R_5= -500 \sin30 \\ ∴R_5= -250N \\ ∴R_5=250N (→) \\ ∴R_3=500 \cos30+500 \sin30-500 \sin30=500 \cos30 \\ ∴R_3=433.013 N \\ Σ F_x=0 \\ ∴R_1-500 \sin30-R_5= 0\\ ∴R_1-250-250= 0 \\ ∴R_1= 500N \\ Σ F_y=0 \\ ∴R_2-500 \cos30= 0 \\ ∴R_2= 500 \cos30= 433.013N $