Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum Oct 28th 2009, 12:35 PM #1 Senior Member   Join Date: Sep 2009 Location: St. John's, NL Posts: 124 angle A mass of 3.700 kg is suspended from a 1.190 m long string. It revolves in a horizontal circle. The tangential speed of the mass is 2.703 m/s. Calculate the angle between the string and the vertical (in degrees). how do you calculate the angle? Fc = mv^2/r = (3.7)(2.703)^2/1.190 = 22.7 N and...   Oct 28th 2009, 02:07 PM #2 Senior Member   Join Date: Sep 2009 Location: india Posts: 409 i am getting 42.89 degrees but it was not really very easy. used T sin theta=m v^2/r and T cos theta= mg gave tan theta= v^2/ rg but r is not given , so used l sin theta= r thus tan theta * sin theta= v^2/ lg=given l= length of string used tan theta= sin theta / cos theta , and wrote cos theta= root over (1- sin^2 theta) reducing the problem to one variable, sin theta. solved sin theta. one root was coming absurd. the other was good -used that one. Last edited by r.samanta; Oct 28th 2009 at 02:35 PM.   Oct 28th 2009, 06:27 PM #3 Senior Member   Join Date: Sep 2009 Location: St. John's, NL Posts: 124 yeah i fogured out after ! and got 42.9 degrees. same answer !! thank you so much for the help tho !    Oct 29th 2009, 12:12 PM #4 Banned   Join Date: Aug 2009 Location: UK Posts: 240 I got the answer = 46.62 degree's K.E transferred = PE gained (1/2)mv^2 = 13.516 J PE = 13.516 J/ (m*g) = h = 0.3727 m 1.19m - 0.3727 = 0.8173 m Sq-rt of ((1.19^2) - (0.8173^2)) = 0.865 m radius tan^-1 (0.865/0.8173) = 46.62 degree's Last edited by Paul46; Oct 29th 2009 at 02:03 PM.   Oct 31st 2009, 03:31 AM #5 Senior Member   Join Date: Sep 2009 Location: india Posts: 409 yes. the answer will be 47.17 degrees. however, paul, my physics was OK , i made a calculation mistake. thank you.  Tags angle Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post bei77 Advanced Mechanics 13 Dec 4th 2014 12:02 PM mybrohshi5 Kinematics and Dynamics 0 Feb 2nd 2010 12:55 PM YamiSorceress Kinematics and Dynamics 2 Oct 25th 2009 12:51 PM christina Kinematics and Dynamics 1 Sep 29th 2009 04:29 AM Air Light and Optics 4 May 13th 2008 05:07 AM