Answer:
a. They both accelerate at the same rate but the forces are different because their masses are different
Step-by-step explanation:
Firstly, as both the balls are falling under the action of gravity, the acceleration of both ball would be constant and equal to acceleration due to gravity (9.8 m/s2). However, the velocity of the objects falling under the action of gravity keep changing.
Secondly, the forces on object can be found by using formula:


Since, both balls are of different material their masses are different. Hence, the forces acting on both balls will be different.