T1T1 Experimentation : F1F1 One of your friends wants to close the door, pushing it in the middle (0.5m from the axis) with a force of 10N : he creates a torque of T 1 = 10 x 0.5 = 5 Nm d1d1

T1T1 F1F1 d1d1 You want to keep open the door ! 1 st solution : you create an equivalent but opposite torque, applying the same force at the same distance on the other face of the door : T 2 = F 2 x d 2 = F 1 x d 1 = T 1, but opposite ! F 2 =F 1 d 2 =d 1 T2T2

T1T1 F1F1 d1 Now, imagine he’s stronger than you ! 2 nd solution : you create an equivalent but opposite torque, applying half of the force at a double distance on the other face of the door : T 2 = F 2 x d 2 = F 1 /2 x 2 x d 1 = 5 x 1 = 5 = T 1, but opposite ! F 2 = F 1 / 2 d 2 =2 x d 1 T2T2

Conclusion : The TORQUE is the rotational effort created by a FORCE, applied at a DISTANCE of the fulcrum (or pivot) : T = F x d The higher the force, the stronger the torque or The bigger the distance, the stronger the force … going further : Think about the possible movement : if you reduce the force to do the same work, what about the distance you move … ? …