How Do You Calculate Angular Acceleration in a Pivoting Rod Problem?

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SUMMARY

The discussion focuses on calculating the angular acceleration of a uniform horizontal rod pivoting about one end when subjected to an external force. The rod has a mass of 2.8 kg and a length of 2.1 m, with the moment of inertia calculated using the formula I = (m ℓ^2) / 3 due to rotation about the endpoint. The applied force of 4.8 N at an angle of 63° generates torque, which is calculated using Torque = R * F * sin(theta). The correct angular acceleration is derived by including the torque due to gravity, which was initially overlooked in the calculations.

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Homework Statement


A uniform horizontal rod of mass 2.8 kg and
length 2.1 m is free to pivot about one end
as shown. The moment of inertia of the rod
about an axis perpendicular to the rod and
through the center of mass is given by I =(m ℓ^2) /12

If a 4.8 N force at an angle of 63◦
to the horizontal acts on the rod as shown, what is the
magnitude of the resulting angular acceleration about the pivot point? The acceleration
of gravity is 9.8 m/s^2
.
Answer in units of rad/s^2


Homework Equations


Sum of the torques = I * a
Torque = R * F * sin(theta)

The Attempt at a Solution



Here is what I have so far:

(sum of the torques) = (Torque of force F)
I * a = R * F * sin(63)
a = (R * F * sin(63)) / I

I = (M * L^2)/3 (It is rotating at its endpoint not at its center of mass)

a = (3 *(R * F * sin(63))) / (M * L^2)
a = (3 *(2.1 * 4.8 * sin(63))) / (2.8 * 2.1^2)
a = 2.1821 rad/s^2 <-----But this answer is incorrect. Where did I go wrong?

 
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Sorry if you came to this but I just figured it out. I forgot the torque due to gravity
 

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