The following are links to *hints and suggestions* on the conceptual problems that appear at the end of each chapter in the lecture book. Note that for virtually all of these questions we are not expecting you to just "know" the answer based on your intuition. In each case, instead, you need to perform some simple analysis first, and from this analysis, draw conclusions on the answers.

Our hope is that through such conceptual questions your intuition on dynamics will develop beyond just remembering methods and procedures. You will see similar conceptual questions on your quizzes and exams in this course.

Use these hints to guide you in your conclusions. *Please post your comments and questions below* regarding these conceptual questions.

Will answers to these questions ever get posted?

The above links provide some very strong hints. Do you have questions on any of these?

Professor Krousgrill,

For question C1.1 Im getting rho = vp^2/(magnitude(ap)sin(theta)). I am confused on what the right answer would be because theta 0 would go to infinity and wouldn't there be two answers because the unit circle repeats values.

When theta = 0, v and a are aligned, which means that the path is locally straight (flat). Rho = infinity for a straight path. Therefore, the math agrees with reality!

Make sense?

Yes that makes sense thank you.

Can we use the equations that are like v_p = v_b + w x r_pb when doing points on different bodies? Or is that solely a rigid body equation and we need to use the ones with v_rel in them for different bodies?

You are correct - the equation you list above can be used only for point P and B on the SAME rigid body.

For C4.17 why are all the summation of forces equal to 0 for system A+B?

The only force acting on either A or B is the impact force. For the system of A+B, this impact force is INTERNAL. Therefore, the net force on A+B is zero, and the linear momentum for the system is conserved in all directions (x, y, n, t).

For question C5.2 why is fh negative, wouldn't it impart a positive CCW moment?

Yes, my goof - the moment due to f should be CCW ("+"). Thanks for bringing that to our attention.