Final answer:
First and third class levers both function based on the principle of torque and involve three forces. The difference lies in the positioning of these forces and the pivot, which leads to varying applications and effects.
Step-by-step explanation:
First class levers and third class levers are alike because they both function based on the principle of torque. Both types of levers involve an input force, an output force, and the force on the pivot or fulcrum. For both, distances from the physical pivot of the lever are crucial.
The key difference lies in the positioning of these forces and the pivot. In a first class lever, the pivot is located between the input and output force. Common examples include a see-saw or a nail puller. The third class lever has both the input force and output force on the same side of the pivot, with the input force being closer to the pivot. Examples of third class levers include shovels, baseball bats, and fishing rods.
This difference in force and pivot position leads to varying applications and effects. For instance, the mechanical advantage (MA) of a first class lever can be greater than one, enabling the output force to be larger than the input force if the lever is long. This is why a long-handled wrench can turn a stubborn bolt with less force. However, a third class lever always has an MA less than one, which means it increases speed and range of motion rather than force.
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