Final answer:
Yes, a set of forces can have a net torque that is zero and a net force that is not zero.The correct option is a).
Step-by-step explanation:
Yes, a set of forces can have a net torque that is zero and a net force that is not zero. The net torque on an object is the result of the vector sum of all the individual torques acting on it, while the net force is the vector sum of all the individual forces acting on it. The individual torques can cancel each other out, resulting in a net torque of zero, even though the individual forces do not cancel each other out, resulting in a net force that is not zero.
For example, imagine a seesaw with a person sitting on one end and a heavy weight on the other end. The person can push down with a small force that exerts a large torque, while the weight can push down with a large force that exerts a small torque. The net torque on the seesaw would be zero, but the net force would not be zero.