WTMA Aptitude Knowledge 3

Question 1

Two gears mesh together. Gear A has 40 teeth and rotates at 100 RPM. Gear B has 20 teeth. How fast does Gear B rotate?

Accepted Answer

200 RPM

Answer

Gear speed ratio is inversely proportional to tooth count: 100 × (40 ÷ 20) = 200 RPM for Gear B.

Question 2

A hydraulic jack has an input piston area of 2 sq in and an output piston area of 20 sq in. A 50 lb force on the input produces what output force?

Accepted Answer

500 lb

Answer

Pascal's Law: output force = input force × (output area ÷ input area) = 50 × (20 ÷ 2) = 500 lb.

Question 3

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

Accepted Answer

Class 1

Answer

A Class 1 lever has the fulcrum between the effort and load, like a seesaw or crowbar.

Question 4

When two resistors of 6 ohms each are connected in parallel, the total resistance is:

Accepted Answer

3 ohms

Answer

Parallel resistors: 1/R = 1/6 + 1/6 = 2/6, so R = 3 ohms.

Question 5

A ramp is 12 feet long and 3 feet high. What is its mechanical advantage?

Accepted Answer

4

Answer

Mechanical advantage of an inclined plane = length ÷ height = 12 ÷ 3 = 4.

WTMA - Wiesen Test of Mechanical Aptitude Practice Test