Net Force Calculator | Find Resultant Force (2024)

Omni's net force calculator allows you to determine the resultant force on a body when several forces act simultaneously on it.

Continue reading this article to know what net force is and how to find the net force on an object. You will also see some examples of net force calculations.

If you need help calculating force from Newton's second law of motion, check out the force calculator.

When a number of forces act simultaneously on an object or a system, the net force or resultant force is the vector sum of all these forces.

We know that the effect of a force $F$F acting on an object of mass $m$m is to accelerate the object according to the equation:

Our magnitude of acceleration calculator is a handy tool in case you want to explore more about acceleration.

The effect of net force would accelerate the object by the same amount as all the actual forces acting on the object. So we can say that the net force is a single force that would produce the same effect as all the forces working together.

Now that we know what net force is, let us understand how to find the net force on an object.

We know that force is a vector quantity, i.e., we need to specify both the magnitude and direction of a force to give its complete description. This means that we should add the individual forces to find the net force just like we add other vectors (check out the vector addition calculator to learn all about vector addition).

To understand this, let us consider a simple scenario where two forces $F_1$F1​ and $F_2$F2​ are acting on a body from two different directions. We can represent these two forces as two vectors $\overrightarrow{F_1}$F1​​ and $\overrightarrow{F_2}$F2​​ acting at angles $\theta_1$θ1​ and $\theta_2$θ2​ (see figure 1).

Using the triangle law of vector addition, we know that if two vectors acting simultaneously on a body can be represented in magnitude and direction by the two sides of a triangle taken in one order, the resultant of these two vectors can be represented in magnitude and direction by the third side of the triangle taken in the opposite order (see the net force diagram in figure 1).

Hence, we get the resultant vector:

To further understand how to find the resultant force, we will consider two simple examples.

First we will consider a simple case where two forces $\overrightarrow{F_1}$F1​​ and $\overrightarrow{F_2}$F2​​ are applied to an object in opposite directions such that;

• $|F_1| = 10\ N$∣F1​∣=10N and $\theta_1 = 0 \degree$θ1​=0°; and
• $|F_2| = 15\ N$∣F2​∣=15N and $\theta_2 = 180 \degree$θ2​=180°.

An example of this case would be when you and your friend are sitting in front of each other and trying to push a book toward each other.

Let us see how to calculate the net force.

1. First, we will find the vertical and horizontal components for both forces:

   • $F_{1x} = 10 \cdot \cos 0 \degree$F1x​=10⋅cos0° and $F_{1y} =10 \cdot \sin 0 \degree$F1y​=10⋅sin0°.
     $\implies F_{1x} = 10$⟹F1x​=10 and $F_{1y} =0$F1y​=0

   • $F_{2x} = 15 \cdot \cos 180 \degree$F2x​=15⋅cos180° and $F_{2y} =15 \cdot \sin 180 \degree$F2y​=15⋅sin180°.
     $\implies F_{1x} = -15$⟹F1x​=−15 and $F_{1y} =0$F1y​=0

2. As the vertical components, $F_{1y}$F1y​ and $F_{2y}$F2y​ are zero, the vertical component of the resultant force will be zero. We can calculate the horizontal component as:

   • $F_x = 10 + (-15)$Fx​=10+(−15), or
     $F_x = -5\ N$Fx​=−5N

3. According to the definition of the net force, the magnitude of the resultant force will be:

   • $F = \sqrt{F_x^2} = 5\ N$F=Fx2​​=5N

   and the direction will be along the direction of the larger force, i.e., $180 \degree$180°.

Now let us consider another case where the magnitude of the forces is the same as in the previous example, but now both the forces act in the same direction, i.e., $\theta_1 = \theta_2 = 180 \degree$θ1​=θ2​=180°. For example, when you and your friend try to push a heavy box together. In this case, the net force would be $25\ N$25N along the direction of both the forces, i.e., $180 \degree$180°.

In the next section, we will see how to solve the same problem using our resultant force calculator.

Let us see how to use the net force calculator:

1. Enter the magnitude ($|F_1| = 10\ N$∣F1​∣=10N and $|F_2| = 15\ N$∣F2​∣=15N) and direction ($\theta_1 = 0 \degree$θ1​=0° and $\theta_2 = 180 \degree$θ2​=180°) of different forces acting on the body. The directions are measured with respect to the positive x-axis.

2. You can add data for up to 10 forces; fields will appear as you need them.

3. The resultant force calculator will display the magnitude ($F = 5\ N$F=5N) and direction ($\theta = 180 \degree$θ=180°) of the net force. It will also show the values of the horizontal and vertical components of the resultant force.

To convert between different units of force, head on to Omni's force converter.

To find the resultant force or net force acting on an object, follow the given instructions:

1. Determine the horizontal and vertical components of all the individual forces by using the formula:

   • Horizontal component –

     Fₓ = F cos θ

   • Vertical component –

     Fᵧ = F sin θ

2. Add the individual horizontal and vertical components to get the horizontal and vertical components of the resultant force.

3. Sum the square of the horizontal and vertical components of the resultant force and take the square root of the result. You will get the magnitude of the resultant force.