Question

Consider an object moving through water (density of 1000 kg/mº) versus air (density of1.29 kg/m).What is the ratio between the forces, i.e. what'sFp(water)Fplair)

Answer 1

Given data:

* The density of water is,

$d_w=1000kgm^{-1}$

* The density of air is,

$d_a=1.29kgm^{-1}$

Solution:

Force in terms of density is,

$F\propto d$

Thus, the ratio of force in water to force in air is,

$\frac{F_{\rho(water)}}{F_{\rho(air)}_{}}=\frac{d_w}{d_a}$

Substituting the known values,

$\begin{gathered} \frac{F_{\rho(water)}}{F_{\rho(air)}}=\frac{1000}{1.29} \\ \frac{F_{\rho(water)}}{F_{\rho(air)}}=775.19 \end{gathered}$

Thus, the ratio between the force at water to force at air is 775.19