# Selina Solutions Class 9 Physics Solutions for Exercise 5A in Chapter 5 - Chapter 5 Upthrust In Fluids Archimedes Principle And Floatation

Question 5 Exercise 5A

What is the cause of upthrust? At which point it can be considered to act?

Liquid exerts pressure at all points and in all directions when contained in a vessel, this pressure on a liquid is the same in all directions and increases with depth inside the liquid.

Upthrust is caused because of a difference in the pressures due to liquid on the two faces of a body (upper and lower) causing a net upward force known as upthrust. The thrust acting on the sides of

the walls of the body get neutralized as they are equal in magnitude and opposite in directions.

The upthrust is considered to act at the center of buoyancy i.e., the center of gravity of the displaced fluid

Video transcript
"hello everyone welcome to lido this is priya and here we have a question about upthrust let us look into the question what is the cause of upthrust at which point it can be considered to act for this you need to understand what is a upthrust to understand about the upthrust upthrust will either is a kind of uh force which acts on the solid which has sinked are inversed into the liquid so before knowing about the up thrust you need to know the property of liquid so liquid exerts pressure in all the directions liquid has the ability to exert pressure in all the directions and in at all the points when it is present inside a vessel this pressure on the liquid is the same in all directions in this direction or in this direction are in this direction the pressure exerting on by this liquid on a material will be same on the all directions but when the depth increases when the depth increases the pressure of the liquid exerting on a substance will also increases and up thrust is caused because of that difference in the pressure due to liquid on the two phases so there is a upper upper phase and lower phase this we call the upper phase this is the upper face and this is a lower face because of the differences between the two pressures because here the depth is different here the depth is different because of the difference in these two pressures due to the two phases which are upper and lower causing a net upward force known as upthrust this causes the net up upward force which we call upthrust and this upthrust acting on the sides of the walls of the body get neutralized as they are equal in magnitude and opposite in direction so this upthrust will acts on the sides of this walls of the object will be neutralized until the magnitude of this body will get neutralized and it is opposite in direction that's why the upthrust is considered to act at the center of bionzi and the center of gravity of the displaced fluid so what is up thrust after us can be considered to act at the center of bionc and as well as the center of gravity of the displaced fluid hope you understand this video if you like my video please subscribe to a little channel and if you have any doubts you can keep a message in comment box thank you"
Related Questions
Exercises

Lido

Courses

Teachers

Book a Demo with us

Syllabus

Maths
CBSE
Maths
ICSE
Science
CBSE

Science
ICSE
English
CBSE
English
ICSE
Coding

Terms & Policies

Selina Question Bank

Maths
Physics
Biology

Allied Question Bank

Chemistry
Connect with us on social media!