A patient is getting his elbow rehabilitated. He is told to lay his elbow flat on a table and lift a a 3.5kg weight by bending his elbow( he's raising his forearm itself and the weight). The weight is 30cm from his elbow. After telling his therapist that it hurts for him to grasp the weight, the patient is then given another weight for him to lift. This time, the weight is 15cm from his elbow.
what mass should the second weight be so that the patient is exerting the same torque ?