Question

An apple is held completely submerged just below the surface of water in a container. The apple is then moved to a deeper point in the water. Compared with the force needed to hold the apple just below the surface, what is the force needed to hold it at the deeper point? (a) Larger (b) The same (c) Smaller (d) Impossible to determine

Short answer

The same force needed to hold it at the deeper point. Hence option (b) is correct answer for this question.

Step-by-step solution

Step 1: Archimedes’ principle

When an object is partially or fully submerged in a fluid, the fluid exerts on the object an upward force called the buoyant force. According to Archimedes’s principle, the magnitude of the buoyant force is equal to the weight of the fluid displaced by the object:

$B={\rho }_{Fluid}g{V}_{disp}$

Where $V_{disp}$is the volume of fluid is displaced and ${\rho }_{Fluid}$is the density of the fluid.

Find the force needed to hold it at the deeper point

• According to above concept we have seen that $B={\rho }_{Fluid}g{V}_{disp}$
• The buoyant force does not depend on the depth of apple in an incompressible fluid.
• So, theforce remains same.

Hence our option (b) will become correct answer for this question