EIAT Forces, Torque, and Motion 3

Question 1

A 900 kg elevator car accelerates downward at 1.5 m/s². What is the net force acting on it? (g = 9.8 m/s²)

Accepted Answer

1,350 N downward

Answer

Net force = mass × acceleration = 900 × 1.5 = 1,350 N downward.

Question 2

What is the mechanical advantage of a pulley system that requires 250 N of effort to lift a 1,000 N load?

Accepted Answer

4

Answer

Mechanical advantage = Load / Effort = 1,000 / 250 = 4.

Question 3

A guide rail exerts a horizontal normal force on an elevator car. This force is best described as:

Accepted Answer

A reaction force perpendicular to the rail surface

Answer

Normal force is always perpendicular to the contact surface, here the rail face.

Question 4

If the rope speed in a traction elevator is 2 m/s and the sheave radius is 0.5 m, what is the sheave's angular velocity?

Accepted Answer

4 rad/s

Answer

ω = v / r = 2 / 0.5 = 4 rad/s.

Question 5

During free fall, what does a person feel regarding their apparent weight?

Accepted Answer

Zero weight (weightlessness)

Answer

In free fall, both the person and scale accelerate at g, so the scale reads zero — apparent weightlessness.

EIAT - Elevator Industry Aptitude Test Practice Test