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BIO Force During a Jump. When jumping straight up from a
Chapter 8, Problem 21E(choose chapter or problem)
BIO Force During a Jump.? When jumping straight up from a crouched position, an average person can reach a maximum height of about 60 cm. During the jump, the person’s body from the knees up typically rises a distance of around 50 cm. To keep the calculations simple and yet get a reasonable result, assume that the ?entire body? rises this much during the jump. (a) With what initial speed does the person leave the ground to reach a height of 60 cm? (b) Draw a free-body diagram of the person during the jump. (c) In terms of this jumper’s weight w, what force does the ground exert on him or her during the jump?
Questions & Answers
QUESTION:
BIO Force During a Jump.? When jumping straight up from a crouched position, an average person can reach a maximum height of about 60 cm. During the jump, the person’s body from the knees up typically rises a distance of around 50 cm. To keep the calculations simple and yet get a reasonable result, assume that the ?entire body? rises this much during the jump. (a) With what initial speed does the person leave the ground to reach a height of 60 cm? (b) Draw a free-body diagram of the person during the jump. (c) In terms of this jumper’s weight w, what force does the ground exert on him or her during the jump?
ANSWER:Solution 21E Step 1: Height reached by the person (h) = 60cm or 0.6m Problem (a) Step 1: To find Initial speed required to reach the height 2 2 v = v 0 + 2aS ----- (1) Here S = h 2 a = -9.8 m/s (jumping upward) v = 0 m/s (final velocity = 0 when maximum height)