tag:blogger.com,1999:blog-5088860151651047897.post658022866704852084..comments2024-03-25T10:56:59.380-04:00Comments on Jacobs Physics: Two Bad QuestionsGreg Jacobshttp://www.blogger.com/profile/03854009948036330746noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-5088860151651047897.post-42816326606477277122011-09-20T07:45:04.850-04:002011-09-20T07:45:04.850-04:00To Anonymous above -- you're right, that's...To Anonymous above -- you're right, that's why this was such a bad problem. The coefficient of static friction is a maximum, and the problem wasn't clear whether or not the incline was as high as it could go without slippage.<br /><br />To JayF, the "coefficient of friction" here is more precisely a drag coefficient, taking into account primarily friction in the axes of the wheels. You're right that there's no sliding, but the situation is not without a force opposing motion, which acts essentially identically to sliding friction. (At least at the introductory level, which is what I'm teaching.)Greg Jacobshttps://www.blogger.com/profile/03854009948036330746noreply@blogger.comtag:blogger.com,1999:blog-5088860151651047897.post-67219702460656702632011-09-20T05:25:36.635-04:002011-09-20T05:25:36.635-04:00Hi Greg,
In your first question, are the shoppin...Hi Greg, <br /><br />In your first question, are the shopping carts on wheels? If so, can't the coefficient of sliding friction can be ignored (no slippage, just rolling), and wouldn't the solution be ~ 10 deg? <br /><br />Jay FoglemanAnonymoushttps://www.blogger.com/profile/06785389386184884713noreply@blogger.comtag:blogger.com,1999:blog-5088860151651047897.post-2658198191532415362011-09-20T01:48:28.137-04:002011-09-20T01:48:28.137-04:00Maybe something else is shown in the figure for pr...Maybe something else is shown in the figure for problem #2, but unless motion is pending, the angle of the incline could have any value from zero to arctan(0.30). The friction coefficient doesn't change, but the normal force changes and therefore the friction force changes as the angle changes.Anonymousnoreply@blogger.com