-45.0 kg girl is standing on a 161 kg plank. The plank, originally at rest, is free to slide on a frozen lak rictionless surface. The girl begins to walk along the plank at a constant velocity of 1.46 m/s relative to lirection the girl is moving in be positive. Indicate the direction with the sign of your answer.) (a) What is her velocity relative to the surface of ice?
Given: The mass of the girl is .
The mass of the plank is .
The initial velocity of the girl with respect to the plank is .
To determine: (a) Velocity of the girl relative to the surface of ice.
It is given that plank is originally at rest so initial velocity of the plank is zero, .
Let the initial velocity of the girl be .
Th velocity of the girl with respect to plank is
The equation for velocity is
................................................ (1)
where is the velocity of the girl relative to ice, is the velocity of girl relative to plank and is the velocity of plank relative to ice.
The momentum is conserved for this girl-plank system. Initial momentum of the system is equal to final momentum.
............................................ (2)
where are the mass of the girl and the plank respectively.
The girl is initially is standing on a plank and the plank is at rest, so the initial velocity of the girl and the plank are zero.
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