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ScienceGeek24
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Homework Statement
Part A : A 0.5 Kg ball is attached to a cord 80 cm long. The ball is whirled in a vertical circle at a constant speed. If the ball takes 0.4 seconds to go around once, what is the tension in the cord at the top and bottom of the circle?
Part B How long does it take for the ball to go around once if the tension in the cord at the top of the circle is zero?
Homework Equations
v=2Pi*R/T
T=m(g+v^2/r) (bottom of the circle)
T=m(g-v^2/r) (top of the circle)
The Attempt at a Solution
For part A i used both of the circular motion formulas to fin the tension and i got totally different answers from what it suppose to be for top and bottom. Top it suppose to be 93.8N and bottom it suppose to be 104 N i got 92.7N top and 102.7 N bottom. ( I do not know if the answer is a print error).
For part A I tried to use v=2Pi*R/T to get the time and i keep getting the same time in part A which is 0.4 secs. But the answer is 1.8 seconds.
Can someone explain to be what I'm doing wrong? thanks!