The boom OAB pivots about point O, while section AB simultaneously extends from within section OA. Determine the velocity and acceleration of the center B of the pulley for the following conditions: θ = 20°, θ˙ = 5 deg /sec, θ¨ = 2 deg /sec2, l = 7 ft, l˙ = 1.5 ft /sec, l¨ = −4 ft /sec2. The quantities l˙ and l¨ are the first and second time derivatives, respectively, of the length l of section AB.

B 24' A Problem 2/137