OAR OAR Mechanical Comprehension: Simple Machines 3

Question 1

A compound pulley system has 4 rope segments supporting the load. What is the mechanical advantage?

Accepted Answer

4

Answer

In a compound pulley, the mechanical advantage equals the number of rope segments supporting the load.

Question 2

A third-class lever has the effort applied between the fulcrum and the load. What is a real-world example?

Accepted Answer

Fishing rod

Answer

A fishing rod is a third-class lever where the effort (hand) is between the fulcrum (grip end) and the load (fish).

Question 3

If a lever arm on the effort side is 4 times longer than the resistance side, the lever provides a mechanical advantage of:

Accepted Answer

4

Answer

Mechanical advantage = effort arm length / resistance arm length = 4/1 = 4.

Question 4

Which simple machine is essentially a circular inclined plane wrapped around a cylinder?

Accepted Answer

Screw

Answer

A screw is an inclined plane (ramp) wrapped helically around a cylinder.

Question 5

A movable pulley is attached to a load. Compared to no pulley, lifting the load requires:

Accepted Answer

Half the force over twice the distance

Answer

A movable pulley halves the required force but requires pulling the rope twice the distance the load travels.

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