problem solving homework 4

# problem solving homework 4 - Should you have some review:...

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Should you have some review: remember the problem that we solved in class? Here is how we can solve it: Method 1: Definition: The magnitude of the turning action about a point = perpendicular distance from turning point (pivot) to the line of action of the force times the magnitude of the force. Moment (or Torque) due to a Force How do you calculate the turning action of  a force? Consider the wrench with a force  on it. Recall:  line of action of the force is  the line along which the force vector lies. Moment : The magnitude of the turning  action about a point  = perpendicular  distance  from turning point (pivot) to the  line of action of the force  times the  magnitude of the force The sign convention : if the tendency to  rotate is  CCW  about the pivot then  plus , if  CW then  negative . Units : Nm (Newton *  meter) or lb-ft  (pound *  foot) d F θ line of  action of  the force F pivot d M = F∙ d F=10 lb o 45 o 30 o 45 o 30 d 30 + 45 = 75 degrees M = F*d perpendicular = = 10 lb * 2 ft * sin75° CW Or if you find the smaller angel in the right triangle : M = F*d perpendicular = = 10 lb * 2 ft * cos15° CW 2 ft

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Moment (or Torque) due to a Force d F θ You can represent force vector as a sum of two  vectors: one is perpendicular to the distance d,  the other one is parallel. NOW you can calculate moment as: The magnitude of the turning action about a point  =  distance  from turning point (pivot) to the point of  application of the force  times the perpendicular  component of the force. M =  d* F* cos
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## This note was uploaded on 04/27/2009 for the course ENGR 111 taught by Professor Walker during the Spring '07 term at Texas A&M.

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problem solving homework 4 - Should you have some review:...

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