Go Back   Physics Help Forum > High School and Pre-University Physics Help > Kinematics and Dynamics

Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

Reply
 
LinkBack Thread Tools Display Modes
Old Oct 28th 2009, 01:35 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...
christina is offline   Reply With Quote
Old Oct 28th 2009, 03:07 PM   #2
Senior Member
 
Join Date: Oct 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 03:35 PM.
r.samanta is offline   Reply With Quote
Old Oct 28th 2009, 07:27 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 !
christina is offline   Reply With Quote
Old Oct 29th 2009, 01:12 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 03:03 PM.
Paul46 is offline   Reply With Quote
Old Oct 31st 2009, 04:31 AM   #5
Senior Member
 
Join Date: Oct 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.
r.samanta is offline   Reply With Quote
Reply

  Physics Help Forum > High School and Pre-University Physics Help > Kinematics and Dynamics

Tags
angle



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Roll angle bei77 Advanced Mechanics 13 Dec 4th 2014 01:02 PM
[SOLVED] Angle :( mybrohshi5 Kinematics and Dynamics 0 Feb 2nd 2010 01:55 PM
Launch Angle YamiSorceress Kinematics and Dynamics 2 Oct 25th 2009 01:51 PM
angle.. christina Kinematics and Dynamics 1 Sep 29th 2009 05:29 AM
Critical Angle, Incident Angle, Refracted Angle... Air Light and Optics 4 May 13th 2008 06:07 AM


Facebook Twitter Google+ RSS Feed