| Questions | 5 |
| Topics | Ceramics, Inertia, Kinetic Friction, Third-Class Lever, Types of Simple Machines |
Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain.
The more mass a substance has the more force is required to move it or to change its direction. This resistance to changes in direction is known as inertia.
Friction resists movement. Kinetic (also called sliding or dynamic) friction resists movement in a direction opposite to the movement. Because it opposes movement, kinetic friction will eventually bring an object to a stop. An example is a rock that's sliding across ice.
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.