# Newton's Second Law

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

## Newton's Second Law

Newton's second law (also known as the Law of Resultant Force) is the force that causes an object or mass to accelerate. The greater the mass to be accelerated, the greater the force required to move the mass. The unit of force is pound, $$lb_f$$ or Newtons.

### Newton's Second Law Formula

$$F = m a \;$$ if the object is free fall with on other force other than gravity.

Where:

$$F$$ = force

$$m$$ = mass

$$a$$ = acceleration

Solve for:

$$m = \frac {F}{a}$$

$$a = \frac {F}{m}$$

## Rotational Newton's Second Law

### Rotational Newton's Second Law Formula

$$\tau = I \alpha$$

Where:

$$\tau$$ (Greek symbol tau) = rotational force

$$I$$ = moment of inertia

$$\alpha$$ (Greek symbol alpha) = angular acceleration

Tags: Equations for Force