Question
Two boys on ice skates hold a rope between them. One is heavier than the other. Do both the boys move when only one boy pulls the rope?
Solution
Initially, both the boys are at rest. Therefore, momentum of boys is zero.
When one of the two boys pulls the other, both the boys will be set into motion and move towards each other to conserve the momentum.
Let 'm' and
be the mass and velocity of light boy, and
'M' and
the mass and velocity of heavy boy, respectively.
According to law of conservation of momentum,
Since velocity of heavier boy is less than the other, therefore, heavier boy will travel less distance than the lighter one.
When one of the two boys pulls the other, both the boys will be set into motion and move towards each other to conserve the momentum.
Let 'm' and
be the mass and velocity of light boy, and 'M' and
the mass and velocity of heavy boy, respectively. According to law of conservation of momentum,
Since velocity of heavier boy is less than the other, therefore, heavier boy will travel less distance than the lighter one.
