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High school regents problem

hi I am new here, but I signed up to ask this question. I was looking at a high school physics exam from last june and one of the questions seems to me like it's unfair. I think they didn't give enough information to solve the problem. here it is;

An 80-kilogram 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?

(1) 0.05 N
(2) 0.4 N
(3) 40 N
(4) 4 N

The correct answer is supposedly #3, but I am really unsure why. The problem and the supplied formula tables made no mention to air resistance or friction forces that oppose his forward momentum. If the skier is already at a constant velocity and we neglect any opposing forces, we shouldn't need to apply any extra forces to keep him moving. Am I mistaken?
 

Doc Al

Mentor
44,803
1,061
You're right, the problem seems to be missing some data. Since he's pushing with his poles, friction must be acting. (I presume that no data about the coefficient of friction was given?)
 

Doc Al

Mentor
44,803
1,061
It turns out that on the official Regents reference sheet, the coefficient of kinetic friction for a waxed ski on snow is given as 0.05.
 
wow that was fast. thanks for your reply.

If that is the case, then I did overlook that. However I looked at the reference sheet again and I don't see it. this is the link for the pdf

http://www.emsc.nysed.gov/osa/reftable/reftablearch/physicstbl.pdf" [Broken]

do you have something different?
 
Last edited by a moderator:
<---- feels kinda dumb

Thanks for your replies doc. I did have the wrong reference tables. I would not have noticed until now.

here is the correct link
http://www.emsc.nysed.gov/osa/reftable/reftablearch/physics06tbl.pdf [Broken]

you are awsome :)
 
Last edited by a moderator:

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