phy121
Your 'cq_1_24.2' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** **
A steel ball of mass 60 grams, moving at 80 cm / sec, collides with a stationary marble of mass 20 grams. As a result of
the collision the steel ball slows to 50 cm / sec and the marble speeds up to 70 cm / sec.
Is the total momentum of the system after collision the same as the total momentum before?
no
What would the marble velocity have to be in order to exactly conserve momentum?
(4800g cm/s - (60g * 50cm/s)) / 20g = 90cm/s
The following sequence of questions, in addition to the principles used in solving the preceding cq problem, should lead you to the correct solution:
What is the initial momentum of the 60 gram ball?
What is the initial momentum of the 20 gram ball?
What is the final momentum of the 60 gram ball?
What is the total initial momentum of the system?
What is the total final momentum of the system?
If momentum is to be conserved, what must therefore be the final momentum of the 20 gram ball?
What must therefore be its velocity?
An alternative breakdown:
What is the initial momentum of the 60 gram ball?
What is the final momentum of the 60 gram ball?
What therefore is the change in momentum of the 60 gram ball?
What therefore is the change in momentum of the 20 gram ball?
What is the initial momentum of the 20 gram ball?
What therefore is the final momentum of the 20 gram ball?
What therefore is the final velocity of the 20 gram ball?
** **
** **
&#Please see my notes and submit a copy of this document with revisions and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end). &#