Mechanical Aptitude Mechanical Aptitude Levers, Pulleys, and Gears 3

Question 1

Three gears are in a line: A drives B, B drives C. If A and C have 30 teeth and B has 15 teeth, which direction does C rotate compared to A?

Accepted Answer

Same direction

Answer

With an odd number of meshed gears in a line, the first and last gears rotate in the same direction; the middle gear is an idler.

Question 2

A movable pulley is attached to the load. How does this affect the effort required to lift the load?

Accepted Answer

Halves the effort needed

Answer

A single movable pulley provides a mechanical advantage of 2, meaning you only need half the force to lift the load.

Question 3

A seesaw with two children is balanced. Child A (60 lbs) sits 4 feet from the fulcrum. Where must Child B (80 lbs) sit to maintain balance?

Accepted Answer

3 feet from fulcrum

Answer

For balance, torques must be equal: 60 × 4 = 80 × d, so d = 240 ÷ 80 = 3 feet.

Question 4

Which type of gear is used to transmit power between shafts at a 90-degree angle?

Accepted Answer

Bevel gears

Answer

Bevel gears have angled teeth cut on a conical surface, making them ideal for transmitting rotation between perpendicular shafts.

Question 5

In a block-and-tackle system, increasing the number of pulleys primarily:

Accepted Answer

Increases the distance through which effort must be applied

Answer

Greater mechanical advantage means less force is needed, but the effort rope must be pulled a proportionally greater distance.

Mechanical Aptitude Test Practice Test