Question

Question:A person in a boat floating in a small pond throws an anchor overboard. What happens to the level of the pond? (a) It rises. (b) It falls. (c) It remains the same.

Short answer

The level of pond falls; hence (b) is correct answer.

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 = $\rho$_FluidgV_disp

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

Find what happens to the level of the pond

• AccordingtoArchimedes’s principle, the level of the pond falls. Its due to the anchor displaces more water while in the boat.
• A floating object displaces a volume of water whose weight is equal to the weight of the object.
• A submerged object displaces a volume of water equal to the volume of the object. A volume of water that weight the same as the anchor will be greater than the volume of the anchor, because the density of anchor is greater than that of water.
• Hence correct option is (b).