A firework of one kind is constructed by fixing two rockets to a rod, with the rockets pointing in opposite directions, as shown. The rod is mounted on a frictionless pivot, allowing the firework to turn in a vertical plane. The firework has weight $W$. The pivot applies a force $R$ to the rod that is equal in size and opposite in direction to $W$. Each rocket applies a force of magnitude $F$ to the rod at a perpendicular distance $d$ from the pivot. The directions of the forces produced by the rockets are always opposite. Air resistance is negligible. Which statement is correct?
- AThe firework is in equilibrium because the resultant force acting on it is zero.
- BThe firework is in equilibrium because the resultant torque acting on it is zero.
- CThe firework is not in equilibrium because the resultant force acting on it is not zero.
- DThe firework is not in equilibrium because the resultant torque acting on it is not zero.