Question

A glider swing uses two linkages to a horizontal platform that swings occupants in a manner that keeps them from tipping. A person is sitting at the center of the platform. The length of the platform is

L =10ft and is suspended by two identical arms (AB and CD) each of length H = 15ft. Determine the angle θ and the angular speed of the arms if the person is moving upward and to the left with a speed of Vp =30ft/s at the angle φ=30 .

D B 3D view Up Ꮎ H B C -L 2D view

Answer 1

34 AB Coso AB Sino and ega HCoso + (Hsino) () -H (sino i troso f) w (-2) i from v = wfk) x AB va =: -w kx (sh sing it coroſ) WH (sino (kx) + cosal Et } ] WH (cino } -cose of WH (-Coro î tsina tsire ? I Now consider the platform As the platform only translates, therefore every point of the platform has same relocity a velocity of point B velocity of vp cos¢ C) + up sing of sve L upsinde Bolan 2. man D v coso

Ø f (3 LAS -WH coso = - Vo cord up cose ît up cind from con wth (Coro) î t wit sind } = v prosdî ty sindi) comparing the ît ? direction terms on to RHS : î direction & -Vecord up card n direction & upsind upsind - Divide egn (5) by egh (4) Upsing upcoso tang WH caso = wh sind wit sino = WH sino wth coso tand = & o = 30° Aur Now from an 6 on ♡ - WHcoso = Upcosa with cose up cosa up 30 ft/sec 15 ft 2 rod/sec Ans 끝