Thread: Physics Quiz 12
View Single Post
  #11   Spotlight this post!  
Unread 04-03-2016, 15:10
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,028
Ether has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond repute
Re: Physics Quiz 12

Quote:
Originally Posted by Rachel Lim View Post
Part 2:
I calculated the torque produced by gravity around point G, and the torque from tension around point E. I then subtracted the two values to find the overall torque.
You have to pick one point, and sum all the external torques around that one point, and set that sum equal to zero. Then solve.

If you pick the point carefully, the equation will have only one variable, so you can solve for it.

Quote:
torque_gravity = (m*g)(distance_AG)(angle_AG to vertical)
= 15582*1.2*sin(20deg)
= 6395
torque_tension = (T)(distance_AE)(angle AE to ET)
= 5448*1.7*sin(140deg)
= 5953
So the overall torque around point A is 442 N*m in the counterclockwise direction.
Gravity and cable tension are not the only forces producing torques around point A.

What other external force(s) is(are) acting on the bucket+rollers+ore free body?


Mentors, Teachers, etc: Rachel is a very bright student. Let's give her (and any other students who may be following the thread) a chance to solve the problem.



Last edited by Ether : 04-03-2016 at 15:35.
Reply With Quote