1. TorqueTorque A turning force

2. Torque (T) – a turning force Torque depends on the linear force applied and the distance from the fulcrum (pivot point) Eg pushing a door is harder from near the hinge than near the handle

3. Torque is a vector Because it is a turning force, the direction is given as clockwise or anticlockwise T = Fd so the units are Nm

4. Common examples of torques are levers, seesaws and bridges The best approach to finding total torque is to find the clockwise torques and balance against the anti clockwise ones

5. Force, Torque and Equilibrium When an object is at rest or moving uniformly it is said to be in equilibrium

6. Forces and Equilibrium 2 forces are in equilibrium if they are equal and opposite 3 forces are in equilibrium if their vector sum = 0 (a closed triangle) Any number of forces are in equilibrium if they form a closed vector diagram

7. A torque needs… A name: “turning force” or “torque” A pivot point = fulcrum A size for the force and the perpendicular distance from the fulcrum A formula: T = Fd (units Nm) A direction: clockwise or anticlockwise direction

8. Solving torque problems Draw a diagram Find and sum the clockwise Torques (T c ) Find and sum the anti-clockwise Torques (T A ) Equilibrium exist if the T A = T c

9. To be in equilibrium… The forces must be balanced The torques must be balanced! If the torques are unbalanced then there is a total force (also called net force) and acceleration happens. The system is not in equilibrium.