Question

if the net force acting on a body is zero then will be the body necessary be in rest position

Answer 1

There is really no rest in the universe. if zero net force is actingon a point mass, then its velocity is unchanged. but if zero net force isacting on a body of finite size, then body will rotate, if net torque is non-zero. e.g. uniform rod, 2 equal opposite forces, one at each end ofrod.