A man swung an object of mass 2 kg in a circular path wit...
A man swung an object of mass 2 kg in a circular path with a rope 1.2 m long. If the object was swung at 120 rev/min, find the tension in the rope.
400
288
240
379
Correct answer is D
m=2kg, r=1.2m, f=120rev/min ; T=?
f= 120rev1min × 1min60s = 2rev\s
w=2πf= 2×π×2= 4πrad\s
T= mv2r, but v = wr
⇒ T = (m)(wr)2r
⇒ T = mw2r
= T = 2× (4π)^2 × 1.2
T = 379N ( to 3 s.f)
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