cq_1_242

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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.

** CQ_1_24.2_labelMessages **

Samantha Rogers

PHY 201

Seed 24.2

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

No the momentums are not the same.

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• 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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&#Very good work. Let me know if you have questions. &#