- #1

ferociablejbear

- 11

- 0

## Homework Statement

A person is standing on tiptoe, with the total weight supported by the force on the toe. A mechanical model for the situation is shown, where T is the force in the Achilles tendon and R is the force on the foot due to the tibia. Find the value of T. Assume the total weight is 484N. Answer in units of N.

R = unknown

T = unknown

Distance of T from point of rotation = 32cm = l

_{2}

Distance of R from point of rotation = 30.29cm = l

_{1}

Angle of T with respect to force acting at point of rotation = 21.2 degrees = θ

Angle of R with respect to force acting of point of rotation = 14.4 degrees = φ

It's a statics problem, so there's no rotational or translational motion. Also, the forces are orthogonal to the radial axis.

## Homework Equations

ΣF

_{y}=Tcosθ-Rcosφ+484N=0

Στ=T*l

_{2}-Rl

_{1}=0

## The Attempt at a Solution

Since there are only two unknowns, I took the relationship between the two torques to find R in terms of T, R=T(l

_{2}/l

_{1}). I then plugged this into the equation for the sum of forces in the y-direction, and I got the answer 672.5992756N for T, but this apparently isn't correct. I really can't figure out what I'm doing wrong, so any help would be appreciated.