A 30-kg girl on friction-free roller blades pushes away a 25-kg ...

[lracut11]

A 30-kg girl on friction-free roller blades pushes away a 25-kg boy also on roller blades at 1 m/s. The girl's speed is
 
  A) 0.45 m/s.
  B) 0.55 m/s.
  C) 0.83 m/s.
  D) 1.2 m/s.

Question 2

A 200-g hockey puck is launched up a ramp that is inclined at a 30 angle above the horizontal.
 
  The coefficients of static and kinetic friction between the puck and the ramp are s = 0.40 and k = 0.30, respectively, and the puck's initial velocity at the base is 3.8 m/s parallel to the sloping surface of the ramp. What speed does the puck have when it slides back down to its starting point?

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Answer to Question 1

Answer: C

Answer to Question 2

2.1 m/s

[lracut11]

Thank you!

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