A push or pull interaction between two objects that can cause a change in an object's velocity (speed or direction), described as a vector quantity. Force is the central concept in classical mechanics, governing everything from how bridges hold up to how rockets launch.
Definition
A push or pull interaction between two objects that can cause a change in an object's velocity (speed or direction), described as a vector quantity.
💡 Intuition
Anything that makes something move, stop, speed up, slow down, or change direction.
🎯 Core Idea
Force is an interaction between objects that changes motion.
Example
Formula
Notation
\vec{F} is force in newtons (N), where 1 N = 1 kg·m/s². The symbol m is mass in kilograms and \vec{a} is acceleration in m/s².
🌟 Why It Matters
Force is the central concept in classical mechanics, governing everything from how bridges hold up to how rockets launch. Every engineering design and safety calculation begins with force analysis.
💭 Hint When Stuck
When solving a force problem, first draw a free-body diagram showing all forces on the object. Then resolve each force into components along your chosen axes. Finally, apply Newton's second law (F_{\text{net}} = ma) separately for each axis to find unknown forces or acceleration.
Formal View
See Also
Compare With Similar Concepts
🚧 Common Stuck Point
Force isn't the same as motion—an object can have forces on it and still not move (if forces balance).
⚠️ Common Mistakes
- Confusing force with velocity or momentum — a force causes acceleration (change in velocity), not velocity itself.
- Forgetting to include all forces in the free-body diagram, especially less obvious ones like normal force or air resistance.
- Assuming that a moving object must have a net force acting on it — objects at constant velocity have zero net force.
Go Deeper
Frequently Asked Questions
What is Force in Physics?
A push or pull interaction between two objects that can cause a change in an object's velocity (speed or direction), described as a vector quantity.
What is the Force formula?
When do you use Force?
When solving a force problem, first draw a free-body diagram showing all forces on the object. Then resolve each force into components along your chosen axes. Finally, apply Newton's second law (F_{\text{net}} = ma) separately for each axis to find unknown forces or acceleration.
Prerequisites
Cross-Subject Connections
How Force Connects to Other Ideas
To understand force, you should first be comfortable with acceleration and mass. Once you have a solid grasp of force, you can move on to newtons first law, newtons second law and newtons third law.
Learn More
🧪 Interactive Playground
Drag to explore. Click to commit changes.