Question

The value of angular momentum of the earth rotating about its own axis is : (Mass of the earth=$5.978\times {10}^{24}kg$ and Radius of earth=$6.378\times {10}^{6}m$)

• A. $7\times {10}^{33}Kg/m^2/sec.$
• B. $70\times {10}^{33}Kg/m^2/sec.$
• C. $0.7\times {10}^{33}Kg/m^2/sec.$
• D. $Zero$

Answer 1

The correct option is A $7\times {10}^{33}Kg/m^2/sec.$

For earth we have moment of inertia as
$I=\frac{2}{5}m{R}^2$
and angular velocity as
$\omega =\frac{2\pi }{T}$
Thus angular momentum is given as
$L=\frac{2}{5}m{R}^2\times \frac{2\pi }{T}$
Substituting the values of the parameters
$L=\frac{2}{5}(5.978\times {10}^{24}kg)(6.378\times {10}^{6}m{)}^2\times \frac{2\pi }{86400s}$
or
$L=7\times {10}^{33}kg/m^2/sec$