- #1
elsternj
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Homework Statement
A large wooden turntable in the shape of a flat uniform disk has a radius of 2.00m and a total mass of 140kg . The turntable is initially rotating at 2.00rad/s about a vertical axis through its center. Suddenly, a 65.0-kg parachutist makes a soft landing on the turntable at a point near the outer edge.
Find the angular speed of the turntable after the parachutist lands. (Assume that you can treat the parachutist as a particle.)
Homework Equations
[tex]\tau[/tex]=Fd
[tex]\tau[/tex]=I[tex]\alpha[/tex]
[tex]\alpha[/tex]=v2/r
v=r[tex]\omega[/tex]
The Attempt at a Solution
Okay this is how I tried to solve this (i could be way off)
[tex]\tau[/tex]=Fd
[tex]\tau[/tex]=(637)(2) < this is the weight of the parachutist multiplied by the radius
[tex]\tau[/tex] = 1274
[tex]\tau[/tex]=I[tex]\alpha[/tex]
1274 = mr2[tex]\alpha[/tex]
1274 = 205(2)2[tex]\alpha[/tex] < this is the torque i found in the previous equation. I added the mass of the the parachutist to the mass of the turntable times the radius squared and solved for [tex]\alpha[/tex]
[tex]\alpha[/tex]=1.5
[tex]\alpha[/tex]=v2/r
v = 1.76
v = r[tex]\omega[/tex]
[tex]\omega[/tex] = .88
Can someone steer me in the right direction? Tell me what I did wrong here? Or a easier approach?