# Mastering Physics - Force on muscles

1. Oct 10, 2013

### oh-jcb

1. The problem statement, all variables and given/known data

Studies of gymnasts show that their high rate of injuries to the Achilles tendon is due to tensions in the tendon that typically reach 9.0 times body weight. That force is provided by a pair of muscles, each exerting a force at 29∘ to the vertical, with their horizontal components opposite.

For a 54-kg gymnast, find the force in each of these muscles.

2. Relevant equations

I imagine it has something to do with a free body diagram.

3. The attempt at a solution
I don't know what forces I should include, if I should break up force into x and y components.

Any help is appreciated.

2. Oct 10, 2013

### Simon Bridge

Good imagination there - that would help. However, this is just a vector sum problem. You have two forces that have to add up to a third force.
The geometry has been described - the exercize is to translate the wordy description into a picture of a triangle.

... what forces are mentioned? What forces are asked for?