WTMA Levers, Pulleys, and Gears 5

Question 1

A worm gear provides high mechanical advantage. What is a key tradeoff compared to spur gears?

Accepted Answer

It is less efficient due to higher friction

Answer

Worm gears have high friction between the worm and wheel, making them less efficient than spur gears but excellent for high reduction ratios.

Question 2

A force of 40 lb is applied at the handle of a nutcracker 6 inches from the hinge. The nut is 1.5 inches from the hinge. What force is applied to the nut?

Accepted Answer

160 lb

Answer

MA = 6/1.5 = 4; Force on nut = 40 × 4 = 160 lb.

Question 3

In a pulley system, why is the actual mechanical advantage always less than the ideal mechanical advantage?

Accepted Answer

Friction in the pulleys wastes some of the input force

Answer

Friction in the pulley bearings and between the rope and pulley reduces the effective force transmitted.

Question 4

A planetary gear system is commonly used because it:

Accepted Answer

Offers high torque in a compact size

Answer

Planetary gears distribute load across multiple planet gears, providing high torque capacity in a compact, coaxial arrangement.

Question 5

A crow bar is being used to pry open a crate. The crow bar is a:

Accepted Answer

First-class lever

Answer

A crowbar used for prying is a first-class lever — the fulcrum (edge of crate) is between the effort (your hands) and the load (lid).

WTMA - Wiesen Test of Mechanical Aptitude Practice Test

WTMA - Wiesen Test of Mechanical Aptitude Practice Test

WTMA Levers, Pulleys, and Gears 5