Physics (AS & A Level) · Oct / Nov 2023 · Paper 11 · Question 13

A type of firework is made by connecting two rockets, facing in opposite directions, to a rod, as shown. The rod is attached to a frictionless pivot so that the firework can rotate in a vertical plane. The firework has weight W. The pivot exerts a force R on the rod that is equal and opposite to W. [diagram: rod with two rockets, forces F at perpendicular distance d from pivot, R and W at pivot] Each rocket exerts a force of magnitude F on the rod at a perpendicular distance d from the pivot. The forces exerted by the rockets are always in opposite directions. Air resistance is negligible. Which statement is correct?

1. AThe firework is in equilibrium because the resultant force acting on it is zero.
2. BThe firework is in equilibrium because the resultant torque acting on it is zero.
3. CThe firework is not in equilibrium because the resultant force acting on it is not zero.
4. DThe firework is not in equilibrium because the resultant torque acting on it is not zero.

As printed in the paper