Question

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online content: site 1
fitness log
describe each class of lever and explain the characteristics of each

Explanation:

• First - class levers: The fulcrum is between the effort and the load. For example, a seesaw or a crowbar. Characteristics: Can be used to gain force or gain distance (depending on the positions of effort, fulcrum, and load). The mechanical advantage can be greater than 1, equal to 1, or less than 1.
• Second - class levers: The load is between the fulcrum and the effort. A wheelbarrow is a common example. Characteristics: Always have a mechanical advantage greater than 1 because the effort arm is longer than the load arm. They are used to multiply force.
• Third - class levers: The effort is between the fulcrum and the load. A pair of tweezers or a human arm (when lifting an object) are examples. Characteristics: Always have a mechanical advantage less than 1 as the effort arm is shorter than the load arm. They are used to gain speed or distance.

Answer:

• First - class levers: The fulcrum lies between the effort and the load (e.g., seesaw, crowbar). It can provide force advantage, distance advantage, or balance, with mechanical advantage (MA) being \(MA=\frac{\text{Effort Arm}}{\text{Load Arm}}\) (MA can be \(>1\), \( = 1\), or \(<1\)).
• Second - class levers: The load is between the fulcrum and the effort (e.g., wheelbarrow). The effort arm is longer than the load arm, so \(MA > 1\), and it multiplies force.
• Third - class levers: The effort is between the fulcrum and the load (e.g., tweezers, human arm lifting). The effort arm is shorter than the load arm, so \(MA < 1\), and it gains speed/distance.