FCTC Test Pulleys, Gears, and Levers Questions and Answers 2

Question 1

A fixed pulley is used to redirect a rope. A firefighter pulls down with 100 lbs of force. How much weight can be lifted?

Accepted Answer

100 lbs

Answer

A single fixed pulley only changes the direction of force and provides no mechanical advantage, so output force equals input force.

Question 2

A two-gear set has a driver gear with 30 teeth and a driven gear with 60 teeth. If the driver gear turns at 200 RPM, at what RPM does the driven gear turn?

Accepted Answer

100 RPM

Answer

Speed ratio equals driver teeth divided by driven teeth: 30 divided by 60 equals 0.5; driven gear RPM equals 200 times 0.5 equals 100 RPM.

Question 3

A Class 2 lever has the load between the fulcrum and the effort. If the load is 150 lbs and the mechanical advantage is 3, how much effort is required?

Accepted Answer

50 lbs

Answer

Effort equals load divided by mechanical advantage: 150 divided by 3 equals 50 lbs.

Question 4

Three equal weights hang from a balanced beam. Two hang 2 feet from the fulcrum on the left side and one hangs on the right side. How far from the fulcrum must the single weight hang to balance the beam?

Accepted Answer

4 feet

Answer

Torque balance: 2W times 2 ft equals 4Wft on the left. To balance: 1W times d equals 4Wft, so d equals 4 feet.

Question 5

A compound gear train has a first stage ratio of 4:1 and a second stage ratio of 3:1. What is the total gear reduction?

Accepted Answer

12:1

Answer

Total ratio equals first stage times second stage: 4 times 3 equals 12:1.

FCTC Test Practice Test

FCTC Test Practice Test

FCTC Test Pulleys, Gears, and Levers Questions and Answers 2