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Question

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**4–15.**

The Achilles tendon force of Ft = 650 N is mobilized when the man tries to stand on his toes. As this is done, each of his feet is subjected to a reactive force of Nf = 400 N. Determine the resultant moment of **F**_{t}** a**nd **N**f about the ankle joint *A*.

**4–16.**

The Achilles tendon force **F**t is mobilized when the man tries to stand on his toes. As this is done, each of his feet is subjected to a reactive force of *N*t = 400 N. If the resultant moment produced by forces **F**t and *N*f about the ankle joint *A *is required to be zero, determine the magnitude of **F**f.

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