# Homework H.4.O

## 8 thoughts on “Homework H.4.O”

1. Edward James Bregi says:

I believe that B is at rest when sphere A makes contact with it

1. Edward James Bregi says:

Should we be leaving our answers in terms of m since there is no value given for m?

2. hu665 says:

How do you write equations between the bumper and A? Do we consider the bump's velocity to be zero before and after the impact?

1. CMK says:

That is correct: in the COR equation, the velocity of the bumper before and after impact is zero.

Please note that linear momentum is NOT conserved for A in the direction normal to the bumper during impact. You will see that from the FBD of A.

3. Sung Namgung says:

I want to verity that should we divide collisions into three different steps?
First FBD is that A and B unattached
Second FBD is that A and B collide,
Third FBD is that A bounced with wall and B moves to the right.

1. CMK says:

All of your FBDs should pertain to the time during which the impact occurs. You will need three FBDs, however: one of A, one of B and one of A+B.