An example of upthrust in physics is a leaf floating on a pond.
Upthrust, also known as buoyant force, is the upward force exerted by a fluid (liquid or gas) that opposes the weight of an immersed object. This force is responsible for the ability of objects to float.
Here's a breakdown of why a leaf floating on a pond demonstrates upthrust:
- Displacement of Water: The leaf, when placed on the water, displaces a certain volume of water.
- Upward Force: According to Archimedes' principle, the upthrust force is equal to the weight of the water displaced by the leaf.
- Equilibrium: The leaf floats because the upthrust force acting upwards is equal to the weight of the leaf acting downwards. If the weight of the leaf were greater than the upthrust, it would sink.
In simpler terms, the water "pushes up" on the leaf with a force equal to the weight of the water the leaf has moved out of the way. This upward push, the upthrust, balances the leaf's weight, allowing it to float.
Other examples of upthrust include:
- A boat floating on water: Similar to the leaf, the boat displaces a volume of water, and the upthrust force balances its weight.
- A balloon rising in the air: The balloon is filled with a gas that is less dense than the surrounding air. The upthrust force exerted by the air on the balloon is greater than the weight of the balloon, causing it to rise.
- A swimmer floating in a pool: A swimmer needs to displace enough water so that the upthrust balances his weight.
