A physics instructor demonstrates energy conservation by releasing a heavy pendulum bob

A physics instructor demonstrates energy conservation by releasing a heavy pendulum bob, as shown in the sketch, allowing it to swing to and fro. What would happen if, in his exuberance, he gave the bob a slight shove as it left his nose? Explain

 

Answer

4) It would come back and hit him in the nose! ( I have demonstrated this one before both with and without the push, and moved right before it would have hit.)