Question

What is the tension between her ears?

• A. $2.1kN$
• B. $2.6kN$
• C. $2.9kN$
• D. None

Answer 1

Answer: (B)

$2.6kN$

$T=GMm[\frac{1}{(R-x{)}^2}-\frac{1}{(R+x{)}^2}]$

$=\frac{GMm}{R^2}[(1+\frac{2x}{R})-(1-\frac{2x}{R})]$

$=\frac{GMm}{R^2}\left(\frac{4x}{R}\right)$

$=\frac{6.67\times {10}^{-11}\times {10}^{31}\times 0.03\times 4\times .06}{(120\times {10}^3{)}^2}=\frac{20\times 24\times 10}{1.73}$
$=2.6kN$.