Physics Help Forum Rolling Ball

 Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

 Oct 25th 2018, 01:01 AM #1 Member   Join Date: Apr 2017 Location: Turkey Posts: 46 Rolling Ball Greeting to all I need small help to solve this problem . I have the answers but i could not reach it . Ans : (a) h = 2.7 R , (b) Fx = -(20/7)mg , Fy = - mg Best regards Razi Note : this problem is not homework ! Attached Thumbnails
 Oct 25th 2018, 02:27 AM #2 Senior Member   Join Date: Apr 2017 Posts: 477 The key to this problem is to see that point at which the sphere fails to complete the loop is not when it's speed is zero ... but when mg = m omega squared r , omega here is the rotational speed around the loop ....r is not the r in the question We have another omega which is the rotation of the sphere itself about it's center of mass .. At the point of failure there is inertial energy stored in the spin of the sphere , as well as energy stored by virtue of it's velocity It's an energy balance problem ...( height of mass of sphere at failure is 2R-r) topsquark, HallsofIvy and Razi like this.
 Oct 25th 2018, 03:40 AM #3 Member   Join Date: Apr 2017 Location: Turkey Posts: 46 Dear oz93666 Thank you sooooo much for your idea , i did it and i have solved the problem Best regards Razi oz93666 likes this.

 Tags ball, rolling

 Thread Tools Display Modes Linear Mode

 Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post errwrsysalan Kinematics and Dynamics 1 May 12th 2016 11:15 AM GrahamJamesK Periodic and Circular Motion 9 Mar 24th 2011 10:13 AM horan6 Kinematics and Dynamics 1 Nov 28th 2009 05:38 PM Hasan1 Kinematics and Dynamics 1 Nov 5th 2008 05:04 PM Aslak Energy and Work 3 Sep 22nd 2008 04:47 PM