Force During a Jump.


An average person can reach a maximum height of about 60 cm when jumping straight up. During the jump itself, the person’s body from the knees up typically rises a distance of around 50 cm.

AWith what initial speed does the person leave the ground to reach a height of 60 cm?

V(final) = V(initial) +2a(delta{y})

0 =V(initial) + 2(-9.8m/s^2)(.60m)


V(initial) = 3.4 m/s

CIn terms of this jumper’s weight w, what

force does the ground exert on him or her during the jump?


V(final) = V(initial) +2a(delta{y})

(3.4m/s)^ = 0 + 2a(.05m)


a = 11.6 m/s^2


n-w = ma


n = w( 1 + a/g)


n = w( 1 + 11.6m/s^2/9.8m/s^2)


n=2.2w