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Grade upto college level Mechanics

How could a person who is at rest on completely frictionless ice covering a pond reach shore? Could she do this by walking, rolling, swinging her arms, or kicking her feet? How could a person be placed in such a position in the first place?

Profile image of Shane Macguire
11 Years agoGrade upto college level
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1 Answer

Profile image of Deepak Patra
11 Years ago
On the frictionless surface, there is no external force acting on the person. Therefore even a gentle push will make her move from the pond towards the shore.
Since the surface is frictionless, the person cannot walk or roll on it. Swinging her arm does not add to any horizontal motion, that could keep her moving towards the shore.
Therefore the person can choose to kick her feet, that will add to its horizontal motion towards and she will manage to reach the store. A person could slide over the surface, reach the pond, and then kick herself to get back.