NCCCO - National Commission for the Certification of Crane Operators Boom Angle and Radius Calculations 1

Question 1

A crane has a 120-foot boom set at a 60-degree angle. What is the approximate working radius from the center pin to the load?

Accepted Answer

60 feet

Answer

72 feet

Answer

96 feet

Answer

104 feet

Question 2

A 150-foot boom is set at a 70-degree angle. What is the approximate working radius?

Accepted Answer

51 feet

Answer

75 feet

Answer

105 feet

Answer

141 feet

Question 3

A crane operator needs to reduce the working radius without changing the boom length or repositioning the crane. What must the operator do?

Accepted Answer

Raise the boom angle

Answer

Lower the boom angle

Answer

Extend the auxiliary jib

Answer

Add counterweight

Question 4

An operator is lifting at a 25-foot radius with an 80-foot boom. He needs to swing the load to a new pick point that requires a 35-foot radius. Before swinging, what must the operator verify?

Accepted Answer

That the load chart permits the rated capacity at the new 35-foot radius

Answer

That the boom angle indicator reads the same value

Answer

That the outrigger pads are wider than the new radius

Answer

That the load weight increases to compensate for the longer radius

Question 5

With an 80-foot boom, an operator raises the boom angle from 60 degrees to 75 degrees. By approximately how many feet does the working radius decrease?

Accepted Answer

19 feet

Answer

8 feet

Answer

14 feet

Answer

27 feet