Levers and Torque in the Human Body

These flashcards cover key vocabulary related to levers, torque, and mechanical advantage in the human body.

Lever

A simple machine that can lift or move an object, consisting of a fulcrum, effort force, and resistance force.

Torque

The turning force applied around an axis, calculated as T = F × d.

Motive Force

The force generated by muscles that causes rotation in a lever system.

Resistive Force

The force that opposes the movement produced by the motive force in a lever system.

Axis of Rotation

The point around which a lever rotates, also known as the fulcrum.

Centric Force

A force applied through the center of mass that does not create torque.

Eccentric Force

A force applied away from the center of mass that creates torque and causes rotation.

Moment Arm

The perpendicular distance from the line of action of a force to the axis of rotation.

Mechanical Advantage

The ratio of the force output to the force input, indicating the efficiency of a lever system.

1st Class Lever

A lever where the axis is in the middle, such as a seesaw.

2nd Class Lever

A lever where the resistance is in the middle, providing force advantage, such as a wheelbarrow.

3rd Class Lever

A lever where the motive force is in the middle, common in human joints, such as an arm during a bicep curl.