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## Homework Statement

I was reviewing some questions from the NYS Regents Physics exam and came across this question, which I could not answer. Here's the question ...

An 80-kg skier slides on waxed skis along a horizontal surface of snow at constant velocity while pushing with his poles. What is the horizontal component of the force pushing him forward?

## Homework Equations

In the horiztonal direction ...

Sum of Forces = mass x acceleration = 0 (constant velocity, therefore a=0)

Sum of Forces = Applied Force - Friction Force = 0

Applied Force = Friction Force

where, Friction Force = Coefficent of Friction x Normal Force

Normal Force = m x g = 80kg * 9.81 m/s^2 = 784.8 N

## The Attempt at a Solution

It seems I cannot determine a solution unless I know what the coefficient of friction is (which was not given in the problem statement). Am I missing something here?

It seems that it is implied that the surface is frictionless, in which case there is no need to apply a force to keep moving at a constant velocity, yet the answer key states that 40N of force are required. If this is indeed the answer, then a coefficient of friction of 0.05 is implied.

Thanks,

Jim