In the circular motion of the hammer, the centripetal force is given by
[tex]F=m \frac{v^2}{r} [/tex]
where m is the mass of the hammer, v its tangential speed and r is the distance from the center of the motion, i.e. the length of the hammer.
Using the data of the problem, we find:
[tex]F=m \frac{v^2}{r}=(7.26 kg) \frac{(31.95 m/s)^2}{1.215 m}=6100 N [/tex]
