# Pendulum problem in KE chapter

Hi Everyone,

My question is as follows:

A bullet of mass m and speed v passes completely through a pendulum bob of mass M. The bullet emerges with a speed v/2. The pendulum bob is suspended by a stiff rod of length and negligible mass. What is the minimum value of v such that the pendulum bob will barely swing through a complete vertical circle? (Use M for M, m for m, l for , and g for gravity, as necessary.)

Any suggestions would be greatly appreciated! Thanks so much!
Sincerely,
esinn08

Doc Al
Mentor
Why don't you give it a shot? Here's a hint: You'll need to use two conservation laws.

Doc Al said:
Why don't you give it a shot? Here's a hint: You'll need to use two conservation laws.

1) conservation of momentum
2) conservation of energy

Am I right?

Doc Al
Mentor
You are correct.