# Torque

## Forces and Rotation

### In Linear Mechanics, The acceleration of an object was dependant only upon the Mass of the object and the Force applied to it. This gave rise to Newton's Second Law. When looking at Forces causing rotation, the picture is not a simple. Consider the two diagrams below :- ### For a set point on a door, the larger the Force applied, the larger the turning effect, therefore the larger the Acceleration will be. This can be easily demonstrated and follows Newton's Second Law. ## Example 1 - ### The above formula applies only if the Force is applied at a right angle to the the radius of motion. If the Force is applied at any other angle the important distance is the perpendicular distance from the line of action to the axis of rotation. The diagram below shows how this is calculated :- ## Example 2 - ## Example 3 -

### A Castle Drawbridge is lowered using two sets of chains as shown in the image below. ### The Drawbridge has a mass of 2500 kg and a length of 4m. When lowered, the chains make an angle of 60o to the horizontal. The Drawbridge is uniform and therefore its center of mass is at a distance of 2m from the axis of rotation. Calculate the Tension in each chain. 