NCEES Statics 4

Question 1

The parallel axis theorem states I = Ic + Ad², where d is:

Accepted Answer

The distance from the centroid to the new parallel axis

Answer

In the parallel axis theorem, d is the perpendicular distance between the centroidal axis and the new parallel axis.

Question 2

A pin-connected truss has 8 members, 5 joints, and 3 support reactions. Using m + r vs 2j, what is its classification?

Accepted Answer

Statically indeterminate (m + r > 2j)

Answer

m + r = 8 + 3 = 11 > 2j = 2(5) = 10, so the truss is statically indeterminate by one degree.

Question 3

Two forces of 100 N each act at 120° apart. What is the magnitude of their resultant?

Accepted Answer

100 N

Answer

R = √(F1² + F2² + 2F1F2cos120°) = √(10000 + 10000 − 10000) = √10000 = 100 N.

Question 4

A wrench applies a 40 N force at 0.25 m from a bolt axis. What moment is developed?

Accepted Answer

10 N·m

Answer

M = F × d = 40 N × 0.25 m = 10 N·m.

Question 5

For a body on an inclined plane of angle θ with static friction coefficient μs, impending slip occurs when:

Accepted Answer

θ = arctan(μs)

Answer

At impending slip, the driving force (W sinθ) equals maximum friction (μs W cosθ), giving tan(θ) = μs.

NCEES Practice Test