A uniform metre rule is pivoted at the 34.0 cm mark, as shown.
The rule balances when a 64g mass is hung from the 4.0 cm mark.
What is the mass of the metre rule?
A man holds a 100N load stationary in his hand. The combined weight of the forearm and hand is
20N. The forearm is held horizontal, as shown.
What is the vertical force F needed in the biceps?