What is Net Force and How It Is Calculated ?

Force is pushing or pulling any item resulting from the object's connection with another object. Without force, nothing can be moved, halted, or shifted. It is a quantitative communication between two actual bodies and their current circumstances. There are different sorts of forces in nature.

Assuming an object is in its movement state, then its present status will be either static or in motion. Its position might be changed, assuming it is pushed or pulled. The outside push or pull applied on the object that changes its present state of movement is known as Force.

Types Of Forces

Force is an actual reason that can meaningfully alter the condition of movement of any item or aspect. Various sorts of forces are recorded below,

• Contact forces: The contact forces are the forces that happen when we apply some work to an object.
• Non-Contact Forces:  The non-contact forces are the forces that occur without contact or connection, apart from a distance.
• Spring Force: This force works in inverse to the dislodging of atoms, like in spring or flexible elastic bands, and so on.
• Gravitational Force: The gravitational force is defined as the force acting between objects due to the presence of matter. For example, Earth’s gravity acts upon objects and is given as,

F_grav = m × g

• Electromagnetic Force : These are the magnetic and electric interactions between atoms and molecules that help in binding and defining the structure of a solid. For example, in a magnet, the north and south poles attract each other, likewise, there are other forces like Tension Force, Normal Force,Air Resistance Force, Applied Force, Spring Force, etc.

Net Force

The net force is the amount of all forces following up on an object in a solitary plane. The net force is significant on the grounds that it depicts the movement of the object and can be utilized to decide speed increase.

⇒Newton's first law of motion makes sense that an object moving will remain moving and an object very still will remain very still except if followed up on by an uneven net force acting on it.

Magnitude of Net Force

• The size of the net force is the way enormous the net force is, which is not the same as the course of the net force. It's the mathematical worth allocated to the force, estimated in the unit Newton's (N).
• The size of the net force is significant in light of the fact that it shows how much force is following up on an item and along these lines how much speed increase the article will insight.
• For example, a net force of 5N will have a much smaller impact on an object compared to a net force of 500N.

Net Force Formula,

The net force equation aggregates the forces following up on an object. Subsequently, the net force is as per the following,

F_Net = F₁ + F₂ + F₃...+ F_N

Where,

F₁, F₂, etc …F_N are the forces acting on the body.

⁛Net force when a body is at rest.

When the object is at rest, the net force formula is given by,

F_Net = F_a + F_g

Where,

F_a =  force applied,

F_g = gravitational force 

When a force is applied to the object, not only is the applied force acting, there are many other forces like gravitational force, frictional force, and the normal force which balances the opposite force. Therefore, the net force is represented as,

F_Net = F_a + F_g + F_f + F_N

Where,

F_a which is applied force,

F_g which is the gravitational force,

F_f which is the frictional force,

F_N which is an Normal force acting .

Solved Examples

1. Consider one block resting on the floor. If this block is balanced by 10 N of normal force and 10 N of gravity force, then what is the value of net force acting on this block?

Given data:
Normal force acting on a block, F_N = 10 N
Force of gravity acting on a block, F_g = -10 N (downward)
The net force acting on a block, F_net =?
Using the formula of net force, (when an object is at rest)
F_net= F_N + F_g
F_net = 10 – 10
F_net = 0 N
Therefore, the net force acting on the block is 0 N.

2. An object is lying on the table. If a 10 N of force is applied to this book, the friction force of 8 N acts on it in the opposite direction. If this object is balanced by 25 N of normal force and gravity force, then calculate the value of net force acting on it.

Given data:
The applied force acting on an object, F_a = 10 N
Friction force acting on an object, F_f = -8 N (left)
Normal force acting on an object, F_N = 25 N
Force of gravity acting on an object, F_g = -25 N (downward)
The net force acting on an object, F_net =?
Using the formula of net force, (when an object is in motion)
F_net = F_a + F_f + F_N + F_g
F_net = 10 – 8 + 25 – 25
F_net = 2 N
Therefore, the net force acting on the object is 2 N.

3. A vehicle is at rest, and a force of 100 N is given to it. If the frictional force acting on it is 50 N, Calculate the net force.

Given data:
Applied force F_a = 100 N
Frictional force F_f = -50 N
The net force formula is given by
F_Net = F_a + F_f
F_Net = 100 – 50
F_Net = 50 N
Therefore, the net force is 50 N

4. A bus gets stuck on the street and 8 persons are pushing this bus in the right direction. All 8 persons are pushing the bus with the following forces: 3N, 4N, 5N, 3N, 7N, 4N, 6N, and 2N. Calculate the total net force applied on the bus.

Force acting on the bus, F₁ = 3 N
Force acting on the bus, F₂ = 4 N
Force acting on the bus, F₃ = 5 N
Force acting on the bus, F₄ = 3 N
Force acting on the bus, F₅ = 7 N
Force acting on the bus, F₆ = 4 N
Force acting on the bus, F₇ = 6N 
Force acting on the bus, F₈ = 2N
Net force acting, F_net = ?
Using the formula of net force of N forces acting upon , 
F_net = F₁ + F₂ + F₃ + F₄ + F₅ + F₆ + F₇ + F₈
F_net = 3 + 4 + 5 + 3 + 7 + 4 + 6 + 2
F_net = 34 N
Therefore, the net force acting on the car is 34 N

5. Two persons A and B are pulling the rope from opposite ends. Person A (standing on the right side) pulls the rope with a force of 35 N and person B (standing on the left side) pulls the rope with a force of 25 N. Calculate the net force acting on the rope.

Given data:
Force acting on the rope, F₁ = 35 N
Force acting on the rope, F₂ = -25 N (left)
The net force acting on the rope, F_net = ?
Using the formula of net force of N forces acting upon,
F_net = F₁ + F₂
F_net = 35 – 25
F_net = 10 N
Therefore, the net force acting on the rope is 10 N.

6. An object is at rest position, and a force of 90 N is applied to it. What will be the net force if frictional force acting on it of 65 N?

Given data:
Applied force F_a = 90 N
Frictional force F_f = -65 N
The net force formula is given by,
F_Net = F_a + F_f
F_Net = 90 – 65
F_Net  = 25 N
Therefore, the net force is 25 N

7. One table resting on the floor. If this table is balanced by 20 N of normal force and 30 N of gravity force, then what is the value of net force acting on this table?

Given data:
Normal force acting on a table, F_N = 20 N
Force of gravity acting on a table, F_g = -30 N (downward)
The net force acting on a table, F_net = ?
Using the formula of net force, (when an object is at rest)
F_net = F_N + F_g
F_net = 20 – 30
F_net = -10 N
Therefore, the net force acting on the block is -10 N.

Also Read,

• Exploring forces
• Interaction of forces
• Newton's Laws of motion