Question

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Problem 3.(25 points) Cathy jumps from a fourth-story window to a firefighter's safety net directly below, as shown in the figure. She is moving downward at a speed of 5.0 m/s at the instant she is 15.0 m above the net. A short while later, she makes impact with the net and stretches the net a distance of 1.0 m before coming to rest. Determine the total time Cathy is in motion, from the moment she is 15.0 m above the net to the moment she comes to rest. (Hint: Treat her motion as two consecutive segments: "free-fall" followed by "slowing.") (17 points) (b) Sketch generic graphs of velocity (v) vs. time (t) and acceleration (a) vs. time (1) for Cathy's motion. The graphs should display correct signs (upward - positive, downward negative) and shapes, but need not include scales and units. (8 points)

Answer 1

Sol (1) Speed at height h=15 m. is uz5m/8. strech of met n = 1 m. Speed gamed by the "Cathy is vedu²+2gh. Therefore, time taken by Cathy to come to rest is on ta (5)*+2x9-81X65-5 1. TX) or t= 1.399727742 Sel.