Question icon
Grade 11Mechanics

Three particles A, B and C, each of mass m, are connected to each other by three massless rigid rods to form a rigid, equilateral triangular body of side . This body is placed on a horizontal frictionless table (x-y plane) and is hinged to it at the point A so that it can move without friction about the vertical axis through A (see figure). The body is set into rotational motion on the table about A with a constant angular velocity omega. (a) Find the magnitude of the horizontal force exerted by the hinge on the body. (b) At time T, when the side BC is parallel to the x-axis, a force F is applied on B along BC (as shown). Obtain the x-component and the y-component of the force exerted by the hinge on the body, immediately after time T.

Profile image of Bidisha Baruah
10 Years agoGrade 11
Answers icon

1 Answer

Profile image of Vikas TU
10 Years ago
At A let Fx and Fy be the hinged forces in horizontal and vertical direction respectively.
At B net Torque = 0
Fx*asin60 +  mga + mgacos60 = Fy*acos60 
root3a/2*Fx + mga  + mga/2= aFy/2
root(3)/2*Fx + 3mg/2 = Fy/2 …................(1)
 
Balncing eqn.
Fx = 0
and 
Fy = mg + mg + mg = 3mg