Engineering Mechanics The triple jump trackandfield event co

Engineering Mechanics

The triple jump track-and-field event consists of a hop, skip and jump, in which the athlete tries to cover as much distance as possible. Shown in the figure is the initial hop. Assuming that he approaches the take oil line (the \"board\") from the left with a horizontal velocity of 10 m/s, remains in contact with the board for 0.18 sec, and takes off at a 50 degree angle with a velocity of 12 m/s, determine the vertical component of the average impulsive force exerted by the ground onto his foot. His mass is 80 kg.

Solution

change in momentum in the vertical direction , p = mvsin50^o - 0

                                                                   p = 80*12sin50^o = 735.4 kg-m/sec

vertical component of impulse force = p/t = 735.4/0.18 = 4085.55 N