How do people lift objects that are heavier

How do people lift objects that are heavier than their own body mass? What kinds of inventions have people come up with to move objects?

Levers!

Definition A lever is a simple machine that changes the amount of force you must exert in order to move an object. What does it mean to exert a force on an object?

Fulcrum: the lever’s fixed point of rotation Load: the mass of an object that is moved or lifted Effort force: the force supplied to any machine to produce an action Effort force Fulcrum Load

E L Effort Arm F Load Arm Effort Arm: the distance between the fulcrum (F) and the effort force (E) Load Arm: the distance between the fulcrum (F) and the load (L)

Class 1 Levers The fulcrum (F) is between the effort force (E) and the load (L) E–F–L E L Effort Arm F Load Arm

Class 1 Levers

Class 2 Levers The load (L) is between the effort force (E) and the fulcrum (F). F–L–E L F E Load Arm Effort Arm

Class 2 Levers A class 2 lever always exerts a greater force on the load than the effort force you exert on the lever.

Class 3 Levers The effort force (E) is exerted between the fulcrum (F) and the load (L) F–E–L E F L Effort Arm Load Arm

Class 3 Levers You must exert a greater force on the lever than the lever exerts on the load – but the load can be moved very quickly.

Body Levers! R = Load (Resistance)