WTMA - Wiesen Test of Mechanical Aptitude Levers, Pulleys, and Gears Questions and Answers

Question 1

In the gear system shown, the driver gear (A) rotates clockwise. An idler gear (B) is placed between gear A and the driven gear (C). In which direction will gear C rotate?

Accepted Answer

Clockwise

Answer

When two gears mesh directly, they rotate in opposite directions. Therefore, if driver gear A rotates clockwise, idler gear B will rotate counter-clockwise. Since gear B (counter-clockwise) meshes with gear C, gear C will rotate in the opposite direction, which is clockwise. The primary function of a single idler gear is to make the driver and driven gears rotate in the same direction.

Question 2

Which of the following lever classes always provides a mechanical advantage greater than 1, meaning the output force is always greater than the effort force?

Accepted Answer

Second-Class Lever

Answer

A second-class lever has the load (resistance) positioned between the fulcrum and the effort. This arrangement ensures the effort arm is always longer than the load arm, resulting in a mechanical advantage that is always greater than 1.

Question 3

A pulley system is set up to lift a heavy engine block. The system uses multiple pulleys, and the rope is threaded so that 4 rope segments are supporting the movable block attached to the engine. Ignoring friction, what is the mechanical advantage of this system?

Accepted Answer

4

Answer

The ideal mechanical advantage (IMA) of a pulley system is equal to the number of rope segments directly supporting the load. In this scenario, there are 4 rope segments supporting the movable block, so the mechanical advantage is 4.

Question 4

A large gear with 60 teeth is driven by a small pinion gear with 20 teeth. If the small pinion gear rotates at 300 RPM, what will be the approximate speed of the large gear?

Accepted Answer

100 RPM

Answer

The gear ratio is calculated by dividing the number of teeth on the driven gear by the number of teeth on the driver gear (60/20 = 3:1). The speed of the output gear is the input speed divided by the gear ratio. Therefore, 300 RPM / 3 = 100 RPM. When a smaller gear drives a larger gear, speed is reduced and torque is increased.

Question 5

Imagine you are using a crowbar to lift a heavy rock. You place a small stone under the crowbar to act as a fulcrum. The rock is the load, and you push down on the end of the crowbar. This is an example of which class of lever?

Accepted Answer

First-Class Lever

Answer

In a first-class lever, the fulcrum is located between the effort (your push) and the load (the rock). A seesaw and a crowbar used in this manner are classic examples of first-class levers.

WTMA - Wiesen Test of Mechanical Aptitude Practice Test

WTMA - Wiesen Test of Mechanical Aptitude Practice Test

WTMA - Wiesen Test of Mechanical Aptitude Levers, Pulleys, and Gears Questions and Answers