Pseudo Force

An observer in a non – inertial frame feels a physically evident but nonexistent force (that is, a frame undergoing acceleration). Only when the presence of such a force is assumed does Newton’s equations of motion hold true within such a reference frame. A pseudo force is the centrifugal force, for example.

Force

Force is a form of influence, a push or a pull, that causes an item (with a specific mass) to change its velocity. In other terms, it causes an object to accelerate. Force is a vector quantity, meaning that its magnitude and direction are both present. Newton (N) is the SI unit of force, and it is denoted by the sign ‘F’.

Types of Force

The several forms of forces present in nature can be divided into two categories:

Contact Force

The Contact Force is activated when two things come into contact with each other, as the name implies. In nature, there are many examples of the Contact Force, like pulling a cart, a ball rolling on the ground stops caused by friction, an airplane’s streamlined body to reduce air resistance, and so on.

Non – contact force

A non-contact force is one that works on an object without actually coming into touch with it. Gravity, that provides weight, is the most well-known non-contact force.

Pseudo force

All masses whose motion is described by a non-inertial reference frame, such as a rotating reference frame, are subject to pseudo force (also known as an inertial force, fictitious force, or d’Alembert force). If a frame of reference accelerates in comparison to a non-accelerating frame, it is considered as pseudo force.

The force F is created by the non-inertial reference frame’s acceleration ‘a’ rather than any physical interaction between two objects. Pseudo forces, as frames, have the ability to accelerate in any direction (but only in direct response to the acceleration of the frame).

Four pseudo forces are specified for frames accelerated in common ways:

A comparable acceleration of the origin in a straight line – rectilinear acceleration – generates one force.

Rotation causes two forces: Coriolis force and centrifugal force.

The fourth aspect is the Euler force, which is caused by a changing rate of rotation.

Formula for Pseudo-Force

A pseudo force usually acts in the opposite direction as the acceleration of an object’s frame of reference. In other words, when an object’s frame of reference accelerates, a pseudo force will always work in the opposite direction. Newton’s second law governs motion, as you may know.

The net force applied on an item is determined by its mass and acceleration. The pseudo-force formula, in a similar spirit, can be stated as follows:

Pseudo force formula F_p= -ma

Here,

F_p= Pseudo force acting on an item.

m = mass of an object.

a = acceleration of the frame of reference of an item.

A negative sign implies that a pseudo force is occurring in the opposite direction of an object’s frame of reference acceleration.

Pseudo Force Examples

Some examples of pseudo force are given below:

Railroad Cart

Imagine, one person is standing on a railroad waggon, while the other is standing along the railway track. When the cart starts going forward, the observer on the ground observes movement in the vehicle but not in the rocks around him. On the other hand, the man standing on the railroad cart perceives the rock on the ground moving at the same rate as the railroad cart, which appears to be stationary to him.

As per the guy standing on the cart, the rocks slide backwards without exerting any force. Because of the cart’s movement, the rocks seem to be shifting. The rocks in the frame look to be being pushed backward by a force. This fictitious power is known as the pseudo force.

Taking a Box that contains a Brick

Assume a brick is kept in a box that is moved about by a rope or a string. The box and the brick accelerate upwards around the inertial frame, which is the ground. The brick looks to be stationary around the box, i.e. the non-inertial frame, while the box appears to be speeding upward. The gravitational force operates on the brick in a downward direction, whereas the ordinary contact force acts upward.

Because the reference frame is accelerating, a pseudo force must operate in the opposite direction of the box’s acceleration. The magnitude of pseudo force is directly proportional to the product of the mass of the brick and the acceleration of the frame. The resultant force acting on the brick must be zero, or the upward and downward pressures must be equal, because it is at rest. As an outcome, the magnitude of net force is equivalent to the sum of the magnitudes of the pseudo force and gravitational force.

Lift

When we descend in a lift, a tremendous force pulls our body higher. Due to this illusion force, things outside the moving lift appear to be going at the same rate as the lift but in the opposite direction. The pseudo force, a fictitious force, is the force that causes something to happen.

Straight Line Acceleration 

It is common to feel “pushed back into the seat” whenever a car accelerates swiftly. In an inertial frame of reference relating to the road, there is no physical force pulling the motorist rearward. Therefore, the accelerating car causes a backward fake force in the driver’s non-inertial reference frame.

Conclusion

Force is a form of influence, a push or a pull, that causes an item (with a specific mass) to change its velocity. In other terms, it causes an object to accelerate. Force is a vector quantity, meaning that its magnitude and direction are both present. Newton (N) is the SI unit of force, and it is denoted by the sign ‘F’. A pseudo force usually acts in the opposite direction as the acceleration of an object’s frame of reference. In other words, when an object’s frame of reference accelerates, a pseudo force will always work in the opposite direction.

Pseudo force formula given as:

Pseudo force formula F_p=-ma