A

Step 1: Calculate the radius of the fan.
The diameter is 120 cm, thus the radius \( r = \frac{120}{2} = 60 \) cm = 0.6 m.

Step 2: Convert the mass of the particle to kg.
The mass is 1 g = 0.001 kg.

Step 3: Calculate the angular velocity in radians per second.
The fan speed is 1500 rpm. Conversion to radians per second:
\( \omega = 1500 \times \frac{2\pi}{60} = 157.08 \text{ rad/s} \).

Step 4: Calculate the centripetal acceleration \( a_c \) at the outer end of the blade.
\( a_c = r \omega^2 = 0.6 \times (157.08)^2 \approx 14.81 \text{ m/s}^2 \).

Step 5: Determine the net force acting on the particle using \( F = m \times a_c \).
\( F = 0.001 \times 14.81 = 0.01481 \text{ N} \).

Step 6: Identify the force exerted on the particle.
This force is the centripetal force exerted by the blade on the particle.

Step 7: Calculate the force the particle exerts back on the blade.
By Newton's third law, the particle exerts an equal and opposite force of 0.01481 N on the blade in the plane of motion.

Therefore, the net force on the particle is approximately 0.01481 N. The blade exerts this force, and the particle also exerts a force of approximately 0.01481 N on the blade.