A uniform rod is 2.0 m long. The rod is pivoted about a horizontal, frictionless pin through one end. The rod is released from rest at the horizontal position. What is the angular acceleration of the rod at the instant the rod makes an angle of 70° with the horizontal? A) 3.7 rad/s² B) 1.3 rad/s² C) 2.5 rad/s² D) 4.9 rad/s² E) 1.9 rad/s²

Question

Quizplus · Accepted Answer

We can use the equation for the angular acceleration of a pivoted rod, which is given by: 
α = (2/3)g/L * sinθ 
where α is the angular acceleration, g is the acceleration due to gravity, L is the length of the rod, and θ is the angle made by the rod with the horizontal. 
Plugging in the values given in the problem, we get: 
α = (2/3)(9.81 m/s^2)/(2.0 m) * sin(70°) 
α ≈ 2.5 rad/s^2

A Uniform Rod Is 2