phy 121
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: ->->->->->->->->->->->-> :
BEFORE
m * v = momentum of object
60g * 80cm/s = 4800 g * cm/s
AFTER
m * v = 60g * 50cm/s = 3000 g * cm/s
m * v = 20g * 70cm/s = 1400 g * cm/s
Total momentum after collision = 3000 g * cm/s + 1400 g * cm/s = 4400 g * cm/s
Total momentum before collision = 4800 g * cm/s
THE TOTAL MOMENTUM IS MORE BEFORE COLLISION.
• 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: ->->->->->->->->->->->-> :
The marble would need momentum of 1800 g * cm/s,
20g * v = 1800 g * cm/s
V = 90 cm/s
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10 min
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&#Very good work. Let me know if you have questions. &#