**Net force** refers to the sum of all the forces that are acting on an object. Imagine a scenario where two forces are applied to an object from opposite directions – one pushing to the right with a force of 10 N and the other pushing to the left with a force of 5 N. The net force in this case would be the difference between these two forces, which is 5 N to the right. It’s like finding the ‘overall force’ on the object, whether it’s a push or a pull. This net force, as defined by Newton’s second law, has a significant impact on the object’s motion. According to the law, if a net force is applied to an object, it can cause the object to accelerate, meaning it will speed up, slow down, or change its direction.

## Formula

The **net force formula** is used to calculate the overall force acting on an object in different situations. When the object is at rest, the net force (F_{net}) is simply the sum of the normal force (F_{N}) and the force of gravity (F_{g}), represented by the equation F_{net} = F_{N} + F_{g}.

In situations where the object is in motion, the net force formula becomes more comprehensive, taking into account additional forces. It includes the applied force (F_{a}) and the frictional force (F_{f}), along with the normal force (F_{N}) and the force of gravity (F_{g}). The formula in this case is expressed as F_{net} = F_{a} + F_{f} + F_{N} + F_{g}.

When an object experiences multiple forces (F_{1}, F_{2}, F_{3}, …, F_{n}), the net force formula expands accordingly. In this scenario, the net force (F_{net}) is determined by summing up all the individual forces acting on the object, leading to the formula F_{net} = F_{1} + F_{2} + F_{3} + … + F_{n}.

### Practice problems

#### Problem #1

In a tug-of-war competition, two teams, team A (on the right side) and team B (on the left side), pull a rope in opposite directions. Team A applies a force of 50 N, while team B exerts a force of 20 N. Calculate the net force on the rope and determine the direction of the resulting motion.

**Solution**

Given data:

- Force applied to the rope by team A, F
_{A}= 50 N - Force applied to the rope by team B, F
_{B}= -20 N (left) - Net force acting on the rope, F
_{net}= ?

Using the formula, when multiple forces are acting on an object:

- F
_{net}= F_{A}+ F_{B} - F
_{net}= 50 – 20 - F
_{net}= 30 N

The net force on the rope is **30 N**. Since the net force is positive, it means that team A’s force is greater than team B’s force. As a result, the rope will move in the direction of team A, which is to the right.

#### Problem #2

A box rests on the floor with a normal force of 8 N supporting it and a gravitational force of 12 N acting downward. What is the magnitude and direction of the net force acting on the box?

**Solution**

Given data:

- Normal force acting on the box, F
_{N}= 8 N - Force of gravity acting on the box, F
_{g}= -12 N (downward) - Net force acting on the box, F
_{net}= ?

Using the formula, when an object is at rest:

- F
_{net}= F_{N}+ F_{g} - F
_{net}= 8 – 12 - F
_{net}= -4 N (downward)

The magnitude of the net force is **4 N**, and the direction is downward (negative sign indicates the downward direction). The net force of 4 N is responsible for keeping the block in equilibrium, as the forces are balanced.

#### Problem #3

Five people come together to help move a van stuck on the road. Each person applies a different force: 5 N, 6 N, 7 N, 4 N, and 8 N. Calculate the total net force exerted on the van to determine if it can be pushed forward and freed from its predicament.

**Solution**

Given data:

- Force applied by the person 1, F
_{1}= 5 N - Force applied by the person 2, F
_{2}= 6 N - Force applied by the person 3, F
_{3}= 7 N - Force applied by the person 4, F
_{4}= 4 N - Force applied by the person 5, F
_{5}= 8 N - Net force acting on the van, F
_{net}= ?

Using the formula, when multiple forces are acting on an object:

- F
_{net}= F_{1}+ F_{2}+ F_{3}+ F_{4}+ F_{5} - F
_{net}= 5 + 6 + 7 + 4 + 8 - F
_{net}= 30 N

Therefore, the net force acting on the van is **30 N**.

#### Problem #4

A crate lies on a table, experiencing a force of 25 N applied in one direction and a frictional force of 7 N opposing it. The crate is balanced by a normal force of 30 N and the force of gravity. Determine the resulting net force on the crate.

**Solution**

Given data:

- Applied force acting on the crate, F
_{a}= 25 N - Friction force acting on the crate, F
_{f}= -7 N (left) - Normal force acting on the crate, F
_{N}= 30 N - Force of gravity acting on the crate, F
_{g}= -30 N (downward) - Net force acting on the crate, F
_{net}= ?

Using the formula, when an object is in motion:

- F
_{net}= F_{a}+ F_{f}+ F_{N}+ F_{g} - F
_{net}= 25 – 7 + 30 – 30 - F
_{net}= 18 N

Therefore, the net force acting on the crate is **18 N**.

## Related

- Balanced force
- Unbalanced force
- Friction
- Tension (physics)
- Applied force
- Normal force
- Drag (physics)
- Gravity
- Centripetal force
- Centrifugal force
- Buoyancy
**Net force**- Compression (physics)

## More topics

## External links

- Determining the Net Force – The Physics Classroom
- Net force – Wikipedia
- Finding the Net Force: Equation & Examples – Study.com
- How to Find Net Force: 9 Steps (with Pictures) – wikiHow
- Net Force – Definition and Example – Turito
- Calculating Acceleration from Force and Mass – CK-12
- Net Force- Resultant Force – Brightstorm
- Net Force – Weebly
- The net force is the combined force of all individual forces acting on an object – Vanderbilt University
- Net Force | Gary Garber’s Blog – BU Blogs
- Net Force – Zona Land Education
- Lesson 19: Net Force – Studyphysics
- Forces and Motion: Basics – PhET
- Newton’s Second Law: Net Force Causes Acceleration – StickMan Physics
- Net Force: Definition, Equation, How to Calculate – Sciencing
- Net Force – Physics Bootcamp
- Force and Mass – The Physics Hypertextbook
- What is net force? | Printable Summary – Virtual Nerd
- How do you determine net force? – Quora
- What is the difference between a force and a net force? – Physics Stack Exchange
- What is the formula for finding net force? – Brainly
- Net Force Calculator – Calculator Academy
- Net external forces netforce – Labster Theory
- Net force – Wikiwand
- Net Force • Forces & Motion – Physics Fox
- Net Force Calculator | Find Resultant Force – Omni Calculator
- How do you determine net force? – Quizlet

Deep

Forceinphysics.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.