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?
gOOD QUESTION
i would think it would be,
torque=massball*length*sin46.6 + massarm*length/2cos*46.6
To find the magnitude of the torque about the shoulder, we can use the formula:
Torque = force × distance
Distance in this case would be the length of the arm, which is given as 68.7 cm. However, since torque calculations require distance to be in meters, we need to convert centimeters to meters by dividing by 100:
Distance = 68.7 cm ÷ 100 = 0.687 m
Now, let's find the force. The force in this case is due to the weight of the steel ball. The weight of an object is given by:
Weight = mass × gravity
where gravity is approximately 9.8 m/s^2.
Weight of the ball = 4.33 kg × 9.8 m/s^2 = 42.434 N
Now, to find the torque, we multiply the force by the distance:
Torque = 42.434 N × 0.687 m
Calculating this gives us the magnitude of the torque about the shoulder.