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(57) A 20.0kg block connected to a 30.0kg block by a string that passes over a l

ID: 1743861 • Letter: #

Question

(57) A 20.0kg block connected to a 30.0kg block by a string that passes over a light, frictionless pulley. The 30.0kg block is connected to a spring that has negligible mass and a force constant of 250 N/m as shown in the figure. The spring is unstretched when the system is as shown in the figure, and the incline is frictionless. The 20.0kg block  ispulled cm down the incline( so that the 30.0kg block is 40.0 cm above the floor and relesed from rest. Find the speed of each block when 30.0kg block is 20.0cm above the floor( that is, when the spring is unstreched).

Explanation / Answer


   (change the figures according to the figuresgiven byyou)                                                 m1 = 25 kg    m2 = 30 kg    k = 175 N / m    x = 20 cm       = 0.20 m    x '= 21 cm       = 0.21 m    y = 41 cm       = 0.41 m    in the system the blocks start from rest so wecan choose that    PEg = 0    if we apply law of conservation of mechanicalenergy from the released position to the final stage    we get         (KE + PEg +PEs)f = (KE + PEg +PEs)i then we get    vf = ............... m / s