| Questions | 5 |
| Topics | Force Lines of Action, Static Friction, Third-Class Lever, Types of Simple Machines, Wheel and Axle |
Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.
Static friction is friction between two or more solid objects that are not moving relative to each other. An example is the friction that prevents a box on a sloped surface from sliding farther down the surface.
A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.
The six types of simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw.
A wheel and axle uses two different diameter wheels mounted to a connecting axle. Force is applied to the larger wheel and large movements of this wheel result in small movements in the smaller wheel. Because a larger movement distance is being translated to a smaller distance, force is increased with a mechanical advantage equal to the ratio of the diameters of the wheels. An example of a wheel and axle is the steering wheel of a car.