Force and Pressure

Introduction

In order to complete a task, force is used. When we talk about pressure, we mean the force applied per unit area.Force is applied per unit area perpendicular to the surface. The unit of pressure measurement is the pascal. A Pascal is defined as the pressure exerted by one Newtonian force on one square unit area.

There are similarities between force and pressure, but in reality, force is the total effect of one object on another, whereas pressure is the specific amount of force applied to a unit area. That is, pressure can be defined as the physical quantity of force distributed over a unit.

Definition of Force and Pressure

The term force is used to describe a type of push or pull. It is something that causes motion in an object. Alternatively, it can be defined as the interaction of two objects. Force has both a magnitude and a direction. Magnitude is a term used to describe the strength of a force. The force changes when the direction, magnitude, or both are changed. The application of force to an object can alter its speed, direction of motion, or shape. Pressure is defined as the amount of force acting on a unit area. 

When an object is pushed or a pull then it is called a force. Action applied on objects results in the motion of an object. When two objects interact, then force comes into play.

• Forces applied in the same direction are added to one another
• Forces acting in the opposite directions, the net force is the difference between the two forces
• If two forces are opposite in directions, then the net force is zero
•  Force has magnitude and direction
• The Strength  of  force is expressed in magnitude
• Change in the magnitude of force changes its effect concerning direction

Force and the State of Motion:

• Speed and direction describe the state of motion of an object
• An object in the state of rest has net-zero speed
• State of an object changes with the change in speed of an object or the direction of motion of an object
• Change in the state of an object can be done by applying force

⮚  The speed of an object increases when force is in the direction of motion

⮚  The speed of an object decreases when the applied force is in the opposite direction

Force and the Shape of an Object:

The object changes its shape under the influence of force. For example, the shape of the dough changes while making chapati.

Without the influence of force, an object cannot change its shape, direction, or speed by itself.

Contact Forces:

Forces acting between two objects when they are in contact with each other, are called contact forces such as Muscular force, Friction, etc.

• Muscular Force: Action of muscles results in force and this is called muscular force

⮚  Muscular Force is capable of performing all activities throughout the day

⮚  Animals like bullocks, etc. carry out physical activities with the application of muscular force

• Friction: It is a reverse force occurring between the object and the surface when the object moves across it

⮚  For example, friction between water and the boat stops or reduces the rowing speed

⮚  The force of friction always acts in the opposite direction and on moving objects

Non-contact Forces:

Forces acting on objects that are not in contact then such forces are called non-contact forces like a magnetic force, gravitational force, etc.

• Magnetic Force: two magnets can exert force on each other without coming in contact with each other

⮚  Two like poles of magnets repel each other and vice versa

⮚  Attraction or repulsion between objects is another push or pull

• Electrostatic Force: When a charged body exerts force then the applied force is called electrostatic force, whic is a non-contact force
• Gravitational Force: Earth applies gravitational force on objects due to which it attracts the earth’s surface

⮚  It is an attractive force and acts on all organisms at all times

⮚  Earth not only has the force of gravity but also other objects in the universe exert a force of gravity on another object

Pressure:

Force acting per unit area is called pressure. It can be expressed as:

Pressure = Force / Area 

The pressure exerted is large when the surface area is small.

• The pressure exerted on the walls of the container by liquids- E.g.- water coming out of the leaking joints is due to the pressure exerted by water on the walls of the pipes
• An inflated balloon is an example of pressure exerted by gases on the walls of a balloon

Atmospheric Pressure:

It is the force exerted on a surface by the air above it as gravity pulls it towards the Earth. The pressure inside our bodies is also equal to the atmospheric pressure that balances the outside pressure and thus it prevents us from crushing under this force of gravity.

In conclusion:-

The term “force” refers to a push or pull. It is something that causes motion in an object. Alternatively, it can be defined as the interaction of two objects. Force has both a magnitude and a direction. Magnitude is a term used to describe the strength of a force. The force changes when the direction, magnitude, or both are changed. The application of force to an object can alter its speed, direction of motion, or shape. Pressure is defined as the amount of force acting on a unit area.