Stand up straight and hold your arms straight in front of you at about 90 degrees. Assume that the extensor muscles in your back work together and that they are the only muscle group acting to stabilize your torso. Question 1: If you hold a 2 kg mass in your hands, consider the force in the back muscles that are needed to stabilize your torso and arm. If you double the mass in your hands, do you predict that the extensor muscle forces will also double? Explain why or why not