3. (20%) A cantilever beam with a lumped mass W is constrained by a spring and a viscous dashpot damper, as shown in Figure 3. If L = 60 in. E! = 103 lb-i112, r; : 20 lb-s/in, W = 2.001} lbs. it = 2 kips/in. no : 0.5 in, 1150 : 10 in/s. determine (1) (10%) the displacement at. t : 1.5 seconds, u(t : 1.5). and (2) (10%) the velocity at t = 1.5 seconds, "r150? : 1.5). E! w Figure 3: Cantilever beam