SIFT Mechanical Comprehension Questions and Answers 2

Question 1

If a lever has a 4-foot effort arm and a 1-foot resistance arm, what is the mechanical advantage?

Accepted Answer

4

Answer

Mechanical advantage of a lever = effort arm length / resistance arm length = 4 / 1 = 4. A force applied at 4 feet can lift 4 times the load at 1 foot.

Question 2

A gear with 10 teeth drives a gear with 40 teeth. What is the gear ratio and what happens to speed?

Accepted Answer

Gear ratio 1:4; the driven gear spins 4 times slower

Answer

Gear ratio = teeth on driven gear / teeth on driving gear = 40/10 = 4:1, so the driven gear rotates at 1/4 the speed of the driver, but torque is multiplied by 4.

Question 3

Which type of pulley system provides a mechanical advantage of 2?

Accepted Answer

A single movable pulley

Answer

A single movable pulley provides a mechanical advantage of 2 because the load is supported by two rope segments, halving the effort required.

Question 4

What is the relationship between pressure and volume in a gas at constant temperature (Boyle's Law)?

Accepted Answer

Pressure and volume are inversely proportional — as one increases, the other decreases

Answer

Boyle's Law states that at constant temperature, the pressure of a gas is inversely proportional to its volume (P₁V₁ = P₂V₂). Compress a gas and its pressure rises.

Question 5

A hydraulic system has a small piston with area 2 in² and a large piston with area 20 in². What force does the large piston exert when 10 lbs is applied to the small piston?

Accepted Answer

100 lb

Answer

By Pascal's Principle, pressure is transmitted equally. P = F/A = 10/2 = 5 psi. Force on large piston = P × A = 5 × 20 = 100 lb.

SIFT Exam Practice Test

SIFT Exam Practice Test

SIFT Mechanical Comprehension Questions and Answers 2