posted by Vishnu on .
An athlete at the gym holds a 4.33 kg steel ball in his hand. His arm is 68.7 cm long and has a mass of 4.69 kg. What is the magnitude of the torque about his shoulder if he holds his arm straight out to his side, parallel to the floor?
Looking at the ball and his arm, and assuming the mass of the arm is at the center of the arm...
torque=massball*length + massarm*length/2
Should the lenght be in centimetres or metres and the mass of the ball in kilograms?
Normally, it does not matter if you place units on your answer. Standard form is n-meters.
What is the magnitude of the torque about his shoulder if he holds his arm straight, but 46.6° below horizontal?
i would think it would be,
torque=massball*length*sin46.6 + massarm*length/2cos*46.6