Final answer:
The 52 kg mass requires the greatest force to move it, according to Newton's second law of motion, where force is directly proportional to mass with constant acceleration.
Step-by-step explanation:
The mass that requires the greatest force to be moved among the given options of 30 kg, 52 kg, 16 kg, and 7 kg, is the mass of 52 kg. According to Newton's second law of motion, the force required to move an object is directly proportional to its mass when acceleration is constant. Therefore, the larger the mass of an object, the greater the force needed to move it. In this context, mass 'b. 52 kg' needs the greatest force to be moved compared to the other masses listed.