Problem

In Example 8.2 on p. 602 we ignored the rotational inertia of the counterweight. Let’s rev...

In Example 8.2 on p. 602 we ignored the rotational inertia of the counterweight. Let’s revisit that example and remove that simplifying assumption. Assume that the arm AD is still a uniform thin bar of length L = 15.7 ft and weight 45 lb. The hinge O is still d = 2.58 ft from the right end of arm, and the 160 lb counterweight C is still δ = 1.4 ft from the hinge. Now model the counterweight as a uniform block of height h = 14 in. and width w = 9 in. With this new assumption, solve for the angular velocity of the arm as it reaches the horizontal position after being nudged from the vertical position. Determine the percent change in angular velocity compared with that found in Example 8.2.