What Causes the Moment About Point A in an Inclined Bar Translation?

[mkkeyan]

Homework Statement

I have a question on pure translation of inclined bar. The problem statement is:
A homogenous slender bar with a mass of 4 kg and a length of 500mm being pushed along the smooth horizontal surface by a horizontal force P=60N. Determine the angle θ for translation. What is the accompanying acceleration? (FBD and kinetic diagram attached)

Homework Equations

I used the following equations:
⅀F_x=ma_x
⅀F_y=0
⅀M_G=0 (since rod is in translation)

The Attempt at a Solution

The results i arrived at are:
θ = 33.4°
a = 15m/s²

My question is, there exists a moment about point A (point of contact between bar and contact surface) equal to 8.26Nm. What is the physical meaning/significance of this moment? Would not the rod rotate about A due to this moment? Requesting for help please.
If my question has already been discussed earlier, request some of you to give link to those threads.
Thanks in advance.

 

[mark726]

Hello,

Thank you for your question. The moment you have calculated is the torque acting on the bar due to the applied force P. This moment is causing the bar to rotate about point A, but since the bar is in pure translation, this rotation is prevented by the contact surface. The bar is constrained to move only in a straight line, and the moment about point A is balanced by the normal reaction force from the surface acting at point A.

In terms of physical significance, this moment is an important factor to consider when designing structures or machines involving inclined bars. If the moment becomes too large, it could cause the bar to rotate and potentially fail. It is important to make sure that the bar is strong enough to withstand the moment and maintain pure translation.

I hope this helps clarify the significance of the moment in this problem. Let me know if you have any further questions.