Points to Remember
• Force acting on a body tends to change its state of rest or of motion or its shape. The SI unit of force is newton.
• Force acts only when two or more objects interact with one other.
• The effect of force can be measured using the physical quantity called pressure.
• Liquids, gases and air also exert pressure.
• All objects on the surface of the Earth experience a constant thrust or force due to the atmosphere.
• Atmospheric pressure can be measured by a device called barometer.
• Friction is the force that opposes the motion of an object.
• Friction is caused by irregularities on the surfaces, which are in contact.
• Friction depends on the nature of the surfaces and mass of the bodies in contact.
• Friction is classified into two types: static friction and kinetic friction. Kinetic friction can be further classified as rolling friction and sliding friction.
• Surface tension is the tendency of liquid surfaces to shrink to have minimum surface area as mush as possible.
• When liquids are flowing there is a frictional force between the layers of the liquid, which oppose their relative motion. This force is called viscous force and the phenomenon is known as viscosity.
• Viscosity is measured by the unit called poise in CGS system and kgm–1s–1 and Nsm–2 in SI.
Buoyant force An upward force exerted by liquid on a floating body.
Force - Ation of push or pull.
Friction - Force produced due to the geometrical dissimilarities of the surface of the bodies which are in relative motion.
Pressure - Force acting on unit area.
Surface tension Force which contracts the surface area of the liquids.
Thrust - Force acting perpendicularly on any given surface area.
1. Fundamentals of Physics (English, Hardcover) David Halliday & Jearl Walker.
2. Principles of Physics, International Student Version (English, Paperback) Jearl Walker, David Halliday, Robert Resnick.
3. Concepts of Physics (Volume-1) 1st Edition (English, Paperback) H. C. Verma.
4. Fundamentals of Physics (English, Hardcover) David Halliday
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Force and Pressure
This activity helps to learn about the Fluid pressure & Pascal’s Law
* Open the Browser and type the URL link given below (or) Scan the QR Code.
* Select the “Fluid Pressure and Pascal’s Law” .You can view this page.
* You can view this page .Touch the play button.
* To get more idea about the Pascal’s Law for fluid pressure through Experiment.
Web link: https://www.youtube.com/watch?v=dx2P7i1GPaw (or) scan the QR Code