Car A was at rest 27.8 ft south of the point O when it was struck in the rear by car B, which was traveling north at a speed vB. Car C, which was traveling west at a speed vC, was 120 ft east of point O at the time of the collision. Cars A and B stuck together and, because the pavement was covered with ice, they slid into the intersection and were struck by car C which had not changed its speed. Measurements based on a photograph taken from a traffic helicopter shortly after the second collision indicated that the positions of the cars, expressed in feet, were rA = ?30.3i + 50.7j, rB = ?30.3i + 61.2j, and rC = ?59.4i ? 45.6j. Knowing that the weights of cars A, B, and C are, respectively, 2800 lb, 3600 lb, and 3200 lb, solve the problems indicated. Knowing that the time elapsed between the first collision and the time the photograph was taken was 3.4 s, determine the initial speeds of cars B and C.

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SE -131