Nice catch marievillafuerte! Yes, that was an error. I've corrected it by uploading an updated calculator screenshot and changed the final written answer.

Thanks again, and best wishes with your studies,

Shaun

Hi marievillafuerte, thanks for the question. It's possible there's a typo in your edition of the text. Perhaps you're using an older printed version? I'm seeing 0.04 in the pdf downloaded from https://openstax.org/details/books/college-physics-ap-courses. Also, we expect a much lower coefficient for steel on ice since, from experience skating, the coefficient of static friction should be very small since it's really slippery standing on ice with skates on. 0.40 is a coefficient comparable to wood on wood (0.50), which is not slippery. Also, https://www.engineeringtoolbox.com/friction-coefficients-d_778.html gives a steel on ice static friction coefficient of 0.03.

The skater moves as a result of being pushed by other skaters so, while she does begin from rest, she will be accelerated by the push from her two fellow skaters.

Hope that helps,

Shaun