3. Rigid Body Wrenches (10 points) Find the resulting wrench at K for a pure force F (no moment) applied at L (F is expressed in L-coordinates). Note that the axes of K and L frames differ by a 180 rotation about z-axis, and are displaced by r = (in K Frame coordinates). Show the numerical relationship between F and the resulting wrench. [3,-7, 21 K L * F