Explosion with two Ice Skaters

  • Thread starter eagles12
  • Start date
  • #1
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Homework Statement



Two ice skaters stand at rest in the center of an ice rink. When they push off one another, the 60 kg skater acquires a speed of .61 m/s. If the speed of the other skater is .8m/s what is this skater's mass?

Homework Equations



explosion- pi=pf

The Attempt at a Solution



1/2m1v1^2=m2v2^2
1/2(60)(.61^2)=m2(.8^2)
11.16=m2(.64)
m2=17.43 but it said this was wrong

but then i got a really big number which doesn't seem right
 

Answers and Replies

  • #2
gneill
Mentor
20,874
2,837
Recheck your formulas. What's the formula for the momentum of a moving body?
 
  • #3
76
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p=mv?
 
  • #5
76
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so do i do m1v1=m2v2 instead of squaring the velocities
 
  • #6
76
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got it! thanks
 
  • #7
BruceW
Homework Helper
3,611
119
yes, that's right man. Its simply conservation of momentum.
 
  • #8
HallsofIvy
Science Advisor
Homework Helper
41,833
956
There is NO "conservation of energy" (which is what you were trying to use first) because the "explosion" (push) adds energy to the system.
 

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