Newton's Second Law Calculator
A 12 kg trolley accelerating at 2.5 m/s² needs a net force of 30 N, from Newton’s second law F = ma.
30 N
- In kN
- 0.03 kN
- In mN
- 30000 mN
- In lbf
- 6.744268293 lbf
- In kgf
- 3.059148639 kgf
- In dyn
- 3000000 dyn
Step-by-step solution
- F = m × a
- F = 12 × 2.5
- F = 30 N
Newton's Second Law Formula
F = m a
F net force (N), m mass (kg), a acceleration (m/s²)
Worked Example
A 12 kg trolley accelerating at 2.5 m/s²:
- F = m × a
- F = 12 × 2.5
- F = 30 N
In mN: 30000 mN · In lbf: 6.744268293 lbf · In kgf: 3.059148639 kgf · In dyn: 3000000 dyn
Mass, weight and pound-force
In US units a mass in pounds accelerated at 1 g produces a force of 1 lbf. The calculator converts lb to kg and lbf to N internally, so mixed units such as pounds of mass and m/s² still give the right answer.
More Forces and Newton’s Laws Calculators
-
Weight Calculator
W = m g
W weight (N), m mass (kg), g gravitational acceleration (9.80665 m/s² standard on Earth)
Example: A 70 kg person standing on Earth: Weight on Earth W = 686.465 N.
-
Gravitational Force Calculator
F = G m₁ m₂ / r²
G = 6.67430 × 10⁻¹¹ N·m²/kg², m₁ and m₂ the masses, r the distance between their centres
Example: Earth (5.972 × 10²⁴ kg) and the Moon (7.348 × 10²² kg) 384,400 km apart: Gravitational force F = 1.98211 × 10²⁰ N.
-
Centripetal Force Calculator
F = m v² / r
m mass, v speed, r radius of the circle; a = v²/r, ω = v/r
Example: A 1000 kg car taking a 50 m radius curve at 10 m/s: Centripetal force F = 2000 N.
-
Hooke's Law Calculator
F = k x
F spring force, k spring constant (stiffness), x extension or compression; energy E = ½kx²
Example: A spring with k = 200 N/m stretched 0.25 m: Spring force F = 50 N.
Frequently asked questions
What is a newton?
One newton is the force that accelerates 1 kg at 1 m/s², so 1 N = 1 kg·m/s². A 100 g apple weighs about 1 N on Earth.
Is F the applied force or the net force?
The net force: the vector sum of all forces. If you push a box with 50 N and friction resists with 20 N, use F = 30 N.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Newton's Second Law Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/newtons-second-law-calculator/
IEEE
Scientific Converters, "Newton's Second Law Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/newtons-second-law-calculator/