A deformable body is under the action of external forces (Fi). The external forces satisfy the following conditions with respect to an inertial frame :
(i) ∑Fi = 0
(ii) ∑ri × Fi = 0
These conditions are:
1
necessary and not sufficient for equilibrium
2
sufficient for equilibrium
3
necessary and sufficient for equilibrium
4
sufficient for unequilibrium
5
None of the above