Step-by-step explanation:
[tex]t = \frac{ \sqrt{w} }{ {d}^{3} } [/tex]
[tex]t = \frac{ \sqrt{5.6 \times {10}^{ - 5} } }{( {1 .4 \times {10}^{ - 4}) }^{3} } [/tex]
[tex]t = \frac{2 \sqrt{14} \times {10}^{ - 3} }{2.744 \times {10}^{ - 12} } [/tex]
[tex]t = 2.72 \times {10}^{9} [/tex]