Chapter 13, Problem 74A

To determine

Net force on a rock.

Answer to Problem 74A

The net force on a rock submerged in water is $24N$ .

Explanation of Solution

Given: Weight of rock, $F_g=45N$

Volume of rock, $V=2.1\times {10}^{23}{m}^3$

Density of water, ${\rho }_{water}=1.00\times {10}^{3}kg/m^3$

Formula used: Net force on an object submerged in water can be obtained by:

  $F_{net}=F_g-F_{buoyant}$

  $F_{net}=F_g-{\rho }_{water}Vg$

Calculation: Net force on a rock submerged in water is:

  $F_{net}=45N-(1.00\times {10}^{3}kg/m^3)(2.1\times {10}^{-3}{m}^3)(9.8N/kg)$

  $F_{net}=24N$

Conclusion: Hence, there is $24N$ net force on a submerged rock.