The arm is outstretched having a mass of 4.2 kg. The hand at the end of arm holds a 6 kg mass. The arm is increased 15 degrees above the horizontal.
i) Determine the torque about the shoulder due to the weights of the arm and 6 kg mass?
ii) When the arm is held in equilibrium by the deltoid muscle whose force on the arm acts 5 degrees beneath the horizontal at a point 18 cm from the shoulder joint, determine the force applied by the muscle?