Calculate force (F = ma), find mass from force and acceleration, or find acceleration from force and mass. Covers Newton's second law, weight force, and gravitational acceleration.
Newton's Second Law states that Force = Mass × Acceleration (F = ma). The force on an object equals its mass multiplied by its acceleration. Force is measured in Newtons (N), mass in kilograms (kg), and acceleration in m/s².
1 Newton is the force required to accelerate 1 kilogram by 1 metre per second squared. 1 N = 1 kg·m/s². The weight of a 100g apple is approximately 1 Newton.
Weight = mass × gravitational acceleration = 70 kg × 9.807 m/s² = 686.5 N. Weight is a force (measured in Newtons), while mass is an amount of matter (measured in kilograms).
The Space Shuttle Main Engine produced approximately 1.86 MN (1,860,000 N) of thrust. The Saturn V rocket produced 33.4 MN total thrust — enough to lift 130,000 kg to orbit.
Mass is the amount of matter in an object, measured in kg. Weight is the gravitational force on that mass, measured in Newtons. An astronaut has the same mass on the Moon as on Earth but weighs 6 times less.
Friction force = coefficient of friction × normal force. For a 70 kg person on a typical floor (μ=0.5): friction = 0.5 × 686 N = 343 N. Friction opposes the direction of motion or attempted motion.
Net force is the vector sum of all forces acting on an object. If net force is zero, the object is in equilibrium (at rest or constant velocity). If net force is non-zero, the object accelerates in the direction of net force.