Phy 201
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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 = (.06 kg)(.8 m/s) + (.02 kg)(0 ms)
= .048 kg m/s
After = (.06 kg)(.5 m/s) + (.02 kg)(.7 ms)
= .03 kg m/s + .014 kg m/s
= .044 kg m/s
.048 kg m/s does not equal .044 kg m/s
#$&*
• What would the marble velocity have to be in order to exactly conserve momentum, assuming the steel ball's velocities to be accurate?
answer/question/discussion: ->->->->->->->->->->->-> :
.048 kg m/s = .03 kg m/s + (.02 kg)(x)
.018 kg m/s = .02 kg (x)
x = .9 m/s
#$&*
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10 minutes
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This looks very good. Let me know if you have any questions.