A 10 kg mass accelerating at 2 m/s²: 10 × 2 = 20 N
A force of 50 N on a 5 kg mass: 50 ÷ 5 = 10 m/s²
A force of 100 N giving 4 m/s²: 100 ÷ 4 = 25 kg
Why your number may differ
F = ma gives the net force. If friction or other forces act too, subtract them first. At speeds close to the speed of light, Newton’s law is not accurate.
Frequently asked questions
What is Newton’s second law?
The force on an object equals its mass times its acceleration: F = m × a. A bigger force gives a bigger acceleration, and a heavier object accelerates less for the same force.
What is a newton?
One newton is the force that gives a 1 kg mass an acceleration of 1 m/s².
How do I find weight?
Weight is the force of gravity on a mass: W = m × g. A 70 kg person has a weight of about 70 × 9.80665 = 686 N.