Hi, would anybody be able to help me with the following question about moments and couples?
A door has a handle which is 0.8m from the hinge. What is the moment of the following forces applied to the handle about the hinge:
a) 12N at right angles to the door
b) 20N at 70° to the door
c) 100N at 25° to the door
Also the questions in the attachments. Thank you!
Moments is distance X force acting at 90 degrees.
If it's at an angle then resolve using Pythagoras or sin/cos rules to find the vertical and horizontal vectors and then multiple the distance by the vector acting at 90•
6a) force= 12N angle=90deg perpendicular distance= 0.8m moment= 12 x 0.8 x sin(90) = 9.6Nmb) force= 20N angle=70 deg perpendicular distance= 0.8mmoment= 20 x 0.8 x sin(70) = 15Nmc) moment= 100 x 0.8 x sin(25) = 33.8Nm