Force (Newton)
Definition
A push or pull on an object measured in Newtons (N). Defined by Newton's Second Law: Force = mass × acceleration (F = ma).
Why is Force (Newton) Important?
Force (Newton) is a core physics concept that describes the fundamental behavior of matter and energy. Understanding this principle enables engineers, students, and scientists to design better systems, solve real-world problems, and predict physical phenomena with precision.
Our physics calculators make it easy to compute values related to this concept, bridging the gap between theoretical understanding and practical application in engineering, education, and research.
What is Force?
Force is a push or pull that can cause an object to accelerate, decelerate, or change direction. Measured in Newtons (N) in SI units or pounds-force (lbf) in imperial. Defined by Newton's Second Law: Force = mass × acceleration.
Newton's Laws of Motion
| Law | Statement | Example |
|---|---|---|
| 1st (Inertia) | Object at rest stays at rest; moving object stays moving unless acted on by force | Seatbelt needed — your body continues forward when car stops |
| 2nd (F=ma) | Force equals mass times acceleration | Heavier objects need more force to accelerate |
| 3rd (Action-Reaction) | Every action has an equal and opposite reaction | Rocket pushes exhaust down, exhaust pushes rocket up |
Force Conversions
| Unit | Equivalent |
|---|---|
| 1 Newton (N) | 0.2248 lbf (force to hold ~100g) |
| 1 pound-force (lbf) | 4.448 N |
| 1 kilogram-force (kgf) | 9.807 N |
| 1 dyne | 0.00001 N |
Everyday Force Examples
| Action | Force (approx) |
|---|---|
| Pressing a keyboard key | ~0.5 N |
| Picking up an apple | ~1 N |
| Pushing a shopping cart | ~20–50 N |
| Your weight (150 lb person) | ~668 N |
| Car engine at highway speed | ~500–3,000 N |
| Bite force (human molar) | ~700 N (160 lbf) |