In Fig. 7-49a, a 2.0 N force is applied to a 4.0 kg block

Chapter , Problem 72

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In Fig. 7-49a, a 2.0 N force is applied to a 4.0 kg block at a downward angle u as the block moves rightward through 1.0 m across a frictionless floor. Find an expression for the speed vf of the block at the end of that distance if the blocks initial velocity is (a) 0 and (b) 1.0 m/s to the right. (c) The situation in Fig. 7-49b is similar in that the block is initially moving at 1.0 m/s to the right, but now the 2.0 N force is directed downward to the left. Find an expression for the speed vf of the block at the end of the 1.0 m distance. (d) Graph all three expressions for vf versus downward angle u for u ! 0( to u ! 90(. Interpret the graphs.