Go Back   Physics Help Forum > College/University Physics Help > Advanced Mechanics

Advanced Mechanics Advanced Mechanics Physics Help Forum

Like Tree2Likes
  • 2 Post By benit13
LinkBack Thread Tools Display Modes
Old Sep 28th 2019, 04:25 AM   #1
Junior Member
Join Date: Sep 2019
Posts: 1
What is the normal force in A and B?

What is the normal force in A and B?-skaermavbild-2019-09-27-kl.-12.20.59.png

A welded square frame consisting of four equal rods each with mass m and length 2l can move in the vertical plane by means of two small wheels in A and B that move frictionally along a horizontal or vertical track, respectively. The disc is released from rest in a position where the sides of the frame are horizontal and vertical respectively. Determine the normal forces in A and B at the beginning moment.

My attempt:

What is the normal force in A and B?-9a2171cd-4af8-4046-9238-aad500abfbf5_img-0389.jpg
What is the normal force in A and B?-img_0390.jpg
I have written on swedish but i think it will be quite easy to understand. As you can see if you watch my solution i get the wrong answer even though i feel like i am doing everything correct. The reaction force in B should be 6/5*mg, where as my answer is 3/10*mg.

Last edited by johanspeed; Sep 28th 2019 at 07:58 AM.
johanspeed is offline   Reply With Quote
Old Sep 29th 2019, 09:53 AM   #2
Senior Member
Woody's Avatar
Join Date: Jun 2016
Location: England
Posts: 1,060
I guess that the only source of force is gravity, which is moving in the ey direction.

At any time after the start time,
there will be lateral forces caused by the geometry.

But at the beginning time the only forces will be in the ey direction,
Woody is offline   Reply With Quote
Old Sep 30th 2019, 02:18 AM   #3
Senior Member
Join Date: Oct 2017
Location: Glasgow
Posts: 474
Originally Posted by johanspeed View Post
Actually i solved it but i dont know how to mark this thread as solved or remove it
Can you please post your answer, just for those who read your thread and are curious?
topsquark and Cervesa like this.
benit13 is offline   Reply With Quote

  Physics Help Forum > College/University Physics Help > Advanced Mechanics

force, force and acceleration, normal, reaction, relative motion

Thread Tools
Display Modes

Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Normal force and gravity force are not action reaction pairs? jlyu002 Kinematics and Dynamics 6 May 21st 2017 09:21 PM
The Slope of a Normal Force vs Applied Force Graph reventon703 Kinematics and Dynamics 1 Apr 11th 2012 05:47 AM
normal contact force with angles furor celtica Kinematics and Dynamics 1 Aug 12th 2011 08:36 AM
Normal Force question bradycat Periodic and Circular Motion 0 Oct 23rd 2010 12:25 PM
normal force? christina Kinematics and Dynamics 1 Oct 12th 2009 12:03 AM

Facebook Twitter Google+ RSS Feed