- #1
azukibean
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Homework Statement
The jumper is 60 kg and wants to beat the school's record jump, 1.1 m. She bends her knees a distance of .5 m before jumping. How many Newtons must Fjump be to for her to beat the record?
Homework Equations
ma = ƩF
V2 - V02 = 2a(X - X0)
My teacher stated I would just need these two equations, and that I would use the latter twice.
The Attempt at a Solution
Jumping up to the apex:
02 - 02 = (2)(-10)(1.1)
She jumps up from rest and the velocity of a mass at the apex is zero; right after she jumps, the only force acting on her is gravity, which is -10 m/s2. I assume 1.1 to be X because she can beat the previous runner's score if she jumps 1.1000001 m, essentially 1.1. So in my solution I could say "she has to jump with a force great than _X."
60a = Fjump - 600
I need acceleration from the previous step.
a) I don't know how to work in the .5 m into the equations. Would I add .5 to X? I would still get a nonsensical answer for step 1.
b) What is wrong with step 1's set up?