Multiple choice

What should be the period of earth's rotation so that every object on the equator is weightless?

  1. 64 min

  2. 34 min

  3. 84 min

  4. 120 min
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fcentripetal = Fgravitation mω2R = mg or, ω = √ (g/R) or, T = 2π√(R/g) Since g = 9.8 m/s2 and r = R = 6.4×106 (radius of the earth) Now, T = 2π√(R/g) = 2π√ (6.4×106/9.8) = 84 min (approx.)  

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