Phy 201
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.
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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?
answer/question/discussion: ->->->->->->->->->->->-> scussion:
#$&* I know, without even working the problem, that the momentum before the collision needs to equal the momentum after the collision. However, by using (m1v1)+(m2v2) = (m1'v1')+(m2'v2'), I get 0.048 kg*m /s = 0.044 kg*m /s. So it's not exact, but the 2 momentums are pretty close to equal.
* What would the marble velocity have to be in order to exactly conserve momentum, assuming the steel ball's velocities to be accurate?
answer/question/discussion: ->->->->->->->->->->->-> scussion:
#$&* I think I understand what to do here. Knowing to initial momentum of the system to be 0.048 kg*m /s, I do .048 kg*m /s = .03 kg*m /s + (.02 * v2'). Solving for v2, I get 0.9m/s or 90 cm/s as the velocity required by the marble to make the momentum before and after the collision equal.
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about 15 minutes....
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Very well done.