#### Answer

The work done by the force is zero.

#### Work Step by Step

The work done by the force on the particle is equal to the change in kinetic energy of the particle. The initial speed of the particle is 30 m/s and the final speed of the particle is 30 m/s. Therefore, the initial kinetic energy is the same as the final kinetic energy.
Since the initial kinetic energy is the same as the final kinetic energy, the change in kinetic energy is zero. Therefore, the work done by the force is zero.