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d3nat
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Homework Statement
A boy and girl are standing on ice skates and pulling on opposite ends of a rope.
Find their velocities the instant they meet.
How long did it take?
Relative speed of approach is 2 m/s
mass of boy = 60kg
mass of girl = 50kg
distance = 5m
Homework Equations
m1v1 + m2v2 = (m1+m2)v
v1 & m1 = boy
v2 & m2 = girl
The Attempt at a Solution
I know that it takes them 2.5 seconds to meet (t = d/v).
I cannot figure out their individual final velocities.
v1+v2 = v_rel
v2 = v_rel - v1
m1(v_rel - v1) + m2v2 = (m1+m2)v
But this leaves me with 2 equations, three unknowns.