A boy runs in a straight line and jumps onto the edge of a merry-go-round on a playground, which is initially not spinning. The boy initially runs tangent to the edge of the merry-go-round and jumps with the same velocity, as shown. After the jump he sits down and spins with the merry-go-round. Take the center of the merry-go-round as the origin of the coordinate system and ignore any frictional effects. Which of the following statements is true for the boy plus merry-go-round system ? Select exactly one answer.

1.The total initial angular momentum is zero and total momentum is not conserved.

2.The total initial angular momentum is non-zero and total angular momentum is conserved.

3.The total initial momentum is non-zero and total momentum is conserved.

4.The total initial angular momentum is zero and total momentum is conserved.

5.The total initial momentum is zero and total momentum is conserved.

6.The total initial momentum is zero and mechanical energy is conserved

p = mv , If R be the radius of the circular path of merry go round . When the boy jumps on the merry gold round , he adds an angular momentum to the system .

Angular momentum of the boy with respect to the center of merry go round

L = r x p = r p sin90.

= r p

= m v r

This is the initial angular momentum of the system of boy and merry go round .

Total final angular momentum of the system will also be equal to initial angular momentum , according to law of conservation of angular momentum , since no external torque is acting on the system.