The force calculator applies F = ma — Newton's second law.
About this calculator
The force calculator applies F = ma — Newton's second law. Enter mass in kilograms and acceleration in m/s² to get the net force in newtons.
Example: a 10 kg box on Earth (g ≈ 9.8 m/s²) weighs about 98 N. A 1200 kg car braking at 3 m/s² needs roughly 3600 N of friction force. Enter those numbers to check your textbook answer.
Force connects to motion and energy across the site. After finding force, use the [[work]] calculator for W = Fs when the object moves. The [[pressure]] calculator divides force by area. The [[momentum]] calculator uses mass and velocity instead of acceleration. For changing speed over time, start with the [[velocity]] calculator (v = u + at).
Common uses
- Weight problems using F = mg on Earth or the Moon
- Finding braking or thrust force from known acceleration
- Class 11 mechanics homework with SI units
- Estimating push force on a trolley in a school lab
- Checking elevator normal force during upward acceleration
Frequently asked questions
What force is needed to accelerate a 5 kg object at 2 m/s²?
F = ma = 5 × 2 = 10 N. Enter mass 5 and acceleration 2. The result is 10 newtons in the direction of acceleration.
How do you calculate weight from mass on Earth?
Weight is a force: F = mg. For a 70 kg person, F = 70 × 9.8 ≈ 686 N. Enter mass 70 and acceleration 9.8 (or 9.80665 for more precision).
What units does the force calculator use?
Mass in kilograms, acceleration in m/s², force in newtons (N). 1 N = 1 kg·m/s². Do not enter grams unless you convert to kg first.
Is force the same as mass times gravity?
Weight is one application of F = ma where a is gravitational acceleration g. On a horizontal surface with no acceleration, support force may equal weight but net force can be zero.