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mybrohshi5
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Homework Statement
A young lady is jumping rope; she always jumps so that both feet leave the ground at the same instant of time. Each of her jumps reaches a height of 14.3 cm off of the ground. (This means that she moves upward by 14.3 cm after her feet leave the ground.) The weight of the young lady is 407 N.
for how long is she in the air each time she jumps?
Homework Equations
d=V(t) + 1/2at2
V=d/t
The Attempt at a Solution
I first calculated her velocity"
Vf2=Vi2 + 2ah
Vf2= 0 + (2)(9.8)(.143)
Vf = 1.67 m/s
Next i tried calculating time:
d=V(t) + 1/2at2
0.143 = 1.67(t) + 1/2(9.8)t2
i used the quadratic formula and came up with
t=0.071 and t=-0.411
I knew it wasnt the negative time cause time can't be negative and 0.071 just seemed too short of a time.
Can anyone confirm that this is correct?
I know the answers are NOT 0.171 or 0.086 from previous attempts.
Thank you
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