Calculator Suite
Force Calculator
Calculate force, mass, or acceleration using Newton's Second Law F = ma
Common Scenarios
Weight Calculation
Calculate the weight (gravitational force) of a 70kg person
Car Engine Force
Force needed to accelerate a car
Rocket Acceleration
Acceleration from rocket thrust
Quick Presets
The Equation
= Net force (in Newtons or pounds-force)
= Mass (in kilograms or pounds-mass)
= Acceleration (in m/s² or ft/s²)
Physical Meaning
Force: A push or pull that can change an object's motion
Mass: The amount of matter in an object (inertia)
Acceleration: The rate of change of velocity
Key Insight: Heavier objects need more force to achieve the same acceleration
Units & Conversions
SI Units: 1 Newton = 1 kg⋅m/s²
Imperial: 1 pound-force = 1 lb⋅ft/s²
Weight vs Mass: Weight = mg (force due to gravity)
Applications
Engineering: Structural analysis and machinery design
Automotive: Engine power and braking systems
Aerospace: Rocket thrust and spacecraft maneuvering
Sports: Impact forces and athletic performance
TL;DR
F = ma is the most famous equation in mechanics. It tells you that force () is required to change an object's speed (), and that massive objects () are harder to move.
What is Newton's Second Law?
Newton's Second Law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.
In simpler terms: Pushing harder makes it go faster. Making it heavier makes it go slower.
How to Use This Calculator
- Choose Your Variable: Are you solving for Force, Mass, or Acceleration?
- Select Units: Choose SI (Newtons/kg) or Imperial (lbf/lbs).
- Enter Values: Input the two known variables.
- Read Results: See the answer and the step-by-step math below.
Real-World Example: Pushing a Car
Scenario:
A 1500 kg car breaks down. You and a friend push it, achieving an acceleration of 0.05 m/s². How much force are you applying?
Analysis:
- Formula:
- Calculation:
- Result: 75 Newtons of force.
3 Key Checks (The "SOP")
Net Force
Remember is the sum of all forces (pushing - friction).
Consistent Units
Using grams? Convert to kg first! (divide by 1000).
Direction
Force and Acceleration always point in the same direction.
Assumptions & Limitations
- Constant Mass: This simple assumes mass doesn't change (unlike a rocket burning fuel).
- Non-Relativistic: Only valid for speeds much slower than light speed.
- Inertial Frame: Valid only in non-accelerating reference frames.
Video Tutorials
Is Force the same as Weight?
Weight is a type of force caused by gravity (). Mass is how much "stuff" is in the object; Weight is how hard gravity pulls on that stuff.
Can I solve for Mass using this?
Yes! Just rearrange the formula: . If you know how hard you pushed (Force) and how fast it sped up (Acceleration), you can weigh the object!
What does "Net Force" mean?
It means the total force after canceling out opposites. If you push right with 10N and friction pushes left with 2N, the Net Force is 8N right.