Levers, Pulleys, and Gears Flashcards

A lever has a 200 lb load placed 2 feet from the fulcrum. How much effort is needed 8 feet from the fulcrum on the other side?

Answer: 50 lb

Using the lever equation: Effort × 8 = 200 × 2, so Effort = 400/8 = 50 lb.

Which class of lever has the fulcrum located between the effort and the load?

Answer: First class

A first-class lever has the fulcrum between the effort and the load, like a seesaw.

A block-and-tackle system uses 4 rope segments supporting the load. If the load weighs 400 lb, what is the ideal effort required?

Answer: 100 lb

With 4 supporting rope segments, the mechanical advantage is 4, so effort = 400 ÷ 4 = 100 lb.

Gear A has 10 teeth and meshes with Gear B, which has 40 teeth. If Gear A rotates at 120 RPM, how fast does Gear B rotate?

Answer: 30 RPM

Speed ratio = teeth of driver ÷ teeth of driven: 120 × (10/40) = 30 RPM.

A wheelbarrow is an example of which lever class?

Answer: Second class

A wheelbarrow is a second-class lever: the wheel (fulcrum) is at one end, load in the middle, and effort at the handles.

When two meshing gears rotate, which statement is always true?

Answer: They rotate in opposite directions

Two directly meshing gears always rotate in opposite directions.

A fixed pulley attached to the ceiling changes the direction of the rope but does NOT increase mechanical advantage. What is its mechanical advantage?

Answer: 1

A single fixed pulley has a mechanical advantage of 1 — it redirects force but does not multiply it.