Work and Power

A 100N girl rides a 50N bicycle a total of 150m at a constant speed. The frictional force against the forward motion of the bicycle equals 25N. How much work does the girl do? Explain your answer.

Answers
Hi Lucy,Thank you so much, it really did help!
priya.singh21
15 September 2016
The girl has to do work against the force of friction so that the work done is Fxd=25x150=3750J.The 100N and 50N of the girl and cycle are vertical forces so don't affect the work done.The numbers are interesting in this question, we have a girl of mass 10kg and a cycle of mass 5kg assuming this is happening on the Earth.  If this were taking place on the Moon the numbers would be a bit better.
Iain S.
16 September 2016
Iain has the correct solution.Ignore Leonora who regularly posts misleading and incorrect solutions.
Sam P.
23 September 2016
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