3. A pendulum consists of a small size block of mass \( \boldsymbol{M}=2 \mathrm{~kg} \) hanging at the bottom end of a massless rigid rod of length \( \boldsymbol{l}=1 \) \( \mathrm{m} \) which has a frictionless pivot at its top end. A ball of mass \( \boldsymbol{m}= \) \( 100 \mathrm{~g} \), moving with horizontal velocity \( \boldsymbol{v} \) impacts block \( \boldsymbol{M} \) in elastic collision. What is the smallest value of \( \boldsymbol{v} \) sufficient to cause the pendulum to swing clear over the top of its arc?
