Question

Quiz #8 MENG 212 At the instant shown, the 50-1b bar rotates clockwise at 2 rad/s. The spring attached to its end ls. The spring attached to its end always remains vertical due to the roller quide at C. If the spring has an unstretched length of 2 ft and, if the angle A is 300 th of 2 ft and, if the angle 0 is 30°, measured from the horizontal, to which the bar rotates before it momentarily stops. Determine the stiffness of the sprinak www 4 ft 2 rad/s 6 ft

Answer 1

By principle of work and energy Theorem V_1 + T_1 = T_2 + V_2 => 1/2[1/3(50/32.2)(6)^2](2)^2 + k/2(4 - 2)^2 = 0 + k/2[4 + 6 sin 30 degree - 2]^2 - 50(3 sin 30 degree] 37.2671 + 2k = 12.5k - 75 k = -112.2671/10.5 k = 10.69 lb/ft