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7.Gravitation
normal
What should be the angular speed of earth, so that body lying on equator may appear weightlessness $ (g = 10\,m/{s^2},\,\,R = 6400\,km)$
A
$\frac{1}{{800}}rad/s$
B
$\frac{1}{{400}}rad/s$
C
$\frac{1}{{600}}rad/s$
D
$\frac{1}{{100}}rad/s$
Solution
(a) $g' = g – {\omega ^2}R{\cos ^2}\lambda $
For weightlessness at equator $\lambda = 0^\circ $ and $g' = 0$
$0 = g – {\omega ^2}R$ $⇒$ $\omega = \sqrt {\frac{g}{R}} = \frac{1}{{800}}\frac{{rad}}{{\sec }}$
Standard 11
Physics
