Final answer:
The force exerted by the biceps is greater than the combined weight due to the concept of torque and the shorter lever arm at the biceps attachment point.
Step-by-step explanation:
The force exerted by the biceps is greater than the combined weight of the forearm, hand, and baseball. This is due to the concept of torque, where the elbow acts as the pivot point. Since the biceps muscle is closer to the pivot point than the weight being lifted (the forearm and hand), it has a shorter lever arm. Accordingly, to maintain equilibrium and hold the weight steady, the biceps must exert a force much greater than the weight of the object being lifted.
For example, if the weight is placed ten times further from the elbow pivot than the biceps attachment, the force exerted by the biceps muscle will be proportionally greater to maintain balance. This is why during a bicep curl, as the forearm is lifted and the distance from the weight to the elbow decreases, the torque required by the biceps muscle will decrease, and thus the amount of force the biceps needs to exert also decreases.