Find masses of two skaters from push-off speeds using impulse

  • Level: Undergrad 
  • Thread starter Thread starter MATRIX-K-
  • Start date Start date
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
2 replies · 3K views
MATRIX-K-
Messages
3
Reaction score
0
I need to determine the masses of two skaters, who together weigh 120kg. They stand still opposite each other. Then they push each other away from away from each other. One of them gain the speed of 3,3m/s and the other one 2,1m/s.
How do you determine their masses?
I know it has something to do with impulses, but I can't figure it out...
 
Physics news on Phys.org
This is a conservation of momtum proplem. Before the skaters push off their momentum is zero, so it must be after the push off. Can you take it from there?
 
[tex]\vec{p}=m\vec{v}[/tex]
where p is momentum. As Integral said,
[tex]\vec{p}_{initial}=\vec{p}_{final}[/tex]
You know initial momentum is zero, so find an expression for the final momentum and set it equal to zero.