An athlete runs horizontally off the edge of a seaside cliff that is above the…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
An athlete runs horizontally off the edge of a seaside cliff that is 8.0m above the surface of the ocean. The cliff overhangs a rocky ledge that rises 2.0m above sea level and extends 3.0m horizontally out from the vertical face of the cliff.
(a) Determine the minimum horizontal speed the athlete must have at the cliff edge to clear the outer edge of the rocky ledge without touching it.
(b) Using the speed found in part (a), calculate the horizontal distance from the cliff face to the point where the athlete first meets the ocean surface.
(c) Determine the magnitude of the athlete’s velocity upon entering the water.
(d) Suppose instead the athlete leaves the cliff with the minimum speed found in part (a) but the ledge is slick with sea spray, reducing the coefficient of kinetic friction between the athlete’s shoes and the ledge to μk=0.20. If the athlete just barely makes contact with the ledge and begins to slide, qualitatively explain whether the athlete will still clear the ledge’s outer edge. Support your explanation with appropriate physical reasoning; no calculation is required.