My name is Alexander FufaeV and here I write about:

# Torque Simply Explained

## Important Formula

What do the formula symbols mean?

## Torque

Unit
Torque describes the rotational effect of a force. It is analogous to the force in linear motion.

## Angular acceleration

Unit
Angular acceleration indicates how fast the angular velocity increases per second. The angular acceleration causes the rotation to become faster and faster.

## Moment of inertia

Unit
Moment of inertia of a body acts like a resistance to rotation and is analogous to mass in a linear motion.

The torque $$\class{green}{\boldsymbol{M}}$$ is defined as follows:

The torque is the cross product of lever-arm length $$\boldsymbol{r}$$ and force $$\boldsymbol{F}$$.

Because of the cross product the torque vector is always perpendicular to $$\boldsymbol{r}$$ and $$\boldsymbol{F}$$! Its magnitude $$|\boldsymbol{r}\times \boldsymbol{F}| = \class{green}{M}$$ is the area spanned by the vectors $$\boldsymbol{r}$$ and $$\boldsymbol{F}$$.

The magnitude of the torque, according to the definition of the cross product, is given by the following formula:

Here $$\varphi$$ is the angle enclosed by the vectors $$\boldsymbol{r}$$ and $$\boldsymbol{F}$$. The torque becomes maximum when the two vectors are orthogonal to each other. So if the angle is $$\varphi = 90^{\circ}$$. Formula 2 then simplifies to the product of the force and lever-arm length.