Forces in Fluids: Buoyant Force

Forces In Fluids A force is a push or pull that acts on an object. EXAMPLE: Weight is the amount of downward pull on a object due to gravity Measuring the unit in force is the newton (N)

BUOYANCY BUOYANCY = the ability to float in a fluid. Examples of fluids = water, air BUOYANT FORCE = the upward force that acts on a submerged object. It acts opposite of gravity

THE BIGGER FORCE WINS, SO THE BLOCK SINKS WEIGHT OF OBJECT THE BIGGER FORCE WINS, SO THE BLOCK SINKS BUOYANT FORCE

This beach ball floats. Why?

Because the Buoyant Force is greater than the weight of the ball.

ARCHIMEDES’ PRINCIPLE The buoyant force acting on a submerged object is equal to the weight of the fluid the object displaces. Video

How Buoyancy Works Example If you could weigh the water that the wood displaces,  you would find that its weight equals the weight of the  wood. Thus, the wood floats. Wood in a pail of water

OBJECT RISES ABOVE SO THE BEACH BALL RISES. WATER Having a lower density than fluid means that the beach ball’s buoyant force is higher than the force of gravity on beach ball/object. SO THE BEACH BALL RISES. WATER

OBJECT SINKS SO THE CINDER BLOCK SINKS. WATER Having a higher density than fluid means that the cinder block’s buoyant force is lower than the force of gravity on cinder block/object SO THE CINDER BLOCK SINKS. WATER

Object Floats SO THE BOOT NEITHER SINKS NOR RISES, it FLOATS WATER Having the same density as water means that the boot’s buoyant force is equal to the gravity’s force on the boot/object. SO THE BOOT NEITHER SINKS NOR RISES, it FLOATS WATER

Which direction does the buoyancy force act on an object? A upward 3.2 Pressure and the Buoyant Forces A B C D Which direction does the buoyancy force act on an object? A upward B downward C to the left of the object D to the right of the object Lesson 2 Review

Where is the pressure the greatest on an object in a fluid? A top 3.2 Pressure and the Buoyant Forces A B C D Where is the pressure the greatest on an object in a fluid? A top B bottom C sides D none of the above Lesson 2 Review