Question

Emily is able to flip a 500 pound tire, but can not deadlift 500 pounds. Which of the following statements best explains why?

A. The act of tire flipping creates a third-class lever, resulting in a mechanical advantage for Emily
B. The act of tire flipping creates a second class lever, resulting in a mechanical advantage for Emily
C. The act of tire flipping creates a first class lever, resulting in a mechanical advantage for Emily

Answer 1

Emily can flip a 500 pound tire due to the mechanical advantage provided by a second class lever, where the resistance (tire) is between the fulcrum and the effort, requiring less force than a deadlift.

Step-by-step explanation:

Emily is able to flip a 500 pound tire, but cannot deadlift the same weight because the action of tire flipping creates a mechanical advantage through the use of a lever system. Specifically, this would be classified as a second class lever. In a second class lever, the resistance (the tire) is between the fulcrum and the point where the effort (applied by Emily) is exerted. This configuration increases the mechanical advantage, meaning less force is required to move the resistance compared to lifting it directly, as in a deadlift.

When Emily flips the tire, the bottom edge of the tire acts as the fulcrum, her hands applying force at another point, and the bulk of the tire's weight is in between. The mechanical advantage (MA) is determined by the ratio of the distances from the fulcrum to the point of effort and to the point of resistance. This leverage means she can move the tire with less effort than lifting the entire 500 pounds directly off the ground would require.