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Hi,
Follow up statements to make sure my understanding is clear (thanks
for the replies)...T or F ... grade my statements...
a) theoretically, it is impossible for the ball to recoil with "exactly"
the same speed as its initial speed (assuming no change in mass)...it must recoil with a slightly lower speed (therefore, it is slightly inelastic and in the CM frame, we would not see the velocity just flipped as with a perfectly elastic collision...Dr. Denker, go easy on me here since this is in opposition to your claim below...)
b) The wall (earth) does recoil with a non-zero momentum...the velocitybeing ridiculously small...the bigger the mass ratio of wall to
On a more positive note, the notion of tiny deflections can beuseful in solving statics problems. It is called "the principle
Regards,Regards,
Rob Spencer
The trick is here:
recoils with a velocity equal in magnitude to its initial velocity.
That's strictly true in the CM frame and approximately /but not exactly/
true in the lab frame.
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